Ok, so… I like a lot the idea that there are Delta Pokémon with different types from the usual ones in Insurgence, especially the fact that they’re either natural or forced mutations intrigues me.
And since I like to make up origin stories to try to explain how something or somebody came to be, I kinda made up some possible origin stories for the Delta we currently see in the game, just for fun 
so if you want you can read them and tell me what you think hahah
For first we have the starters, Bulbasaur, Squirtle and Charmander. In the Pokédex it says that the three were created in experiments by certain scientists so I tried to guess what kind of experiments they were: for first, I thought scientists were trying to force a Charmander into gaining the Dragon type through the substitution of its lizard cells with stronger dragon scales created or extracted from other dragon Pokémon, but it was too young to survive the operation and as soon as the scientists were trying to implant the new cells Charmander passed away. That’s where the scientists started developing the idea of a Ghost type inclusion in the experiment: after the deletion of Charmander’s skin, a new team joined the experiment and imbued a new “ghost” flame created by Chandelures, successfully reviving Charmander’s brain. When it woke up again, it had a skeleton looking body but couldn’t feel anything but cold. After the revival was completed (that’s why Ghost type is first and Dragon second), the process to introduce Dragon cells in Charmander restarted, and new scales were added to its body. The dead cells of Charmander quickly “ghostified” the Dragon ones, creating a pale dead-white colour, while its internal flame pouch started heating up again, slowly burning the zombie body of the Pokémon, eventually going full-black in Charizard stage.
At the same time, other experiments were made on a Bulbasaur and a Squirtle. As scientists thought it would’ve been better for a Blastoise to develop more physical attacks, and that it was too reckless to rely on water blasts. So they tried to imbue the Fighting type in the Pokémon. To do so, they temporarily blocked its spouts of water and blindfolded it, with the help of Fighting-type experts. Squirtle was way too weak to develop a knack for Fighting type moves quickly, so it started enhancing its strategy skills first, relying onto cheating methods like biting and taunting. As soon as it started growing “evil” (Dark type developing first), it was eventually time for Squirtle to fight for real, and exploiting its shell it started training to become a Fighting type with a very passionate love for dirty blows.
Bulbasaur’s way was a lot less physical, because scientists were trying to make it develop psychic powers.Through the seed on its back, they started enhancing the strength of its poison to use it against itself, after injecting various drugs to inhibit Bulbasaur’s immunity to poison. It eventually grew a lot weaker and more prone to diseases, even to the point of killing its Grass type. Bulbasaur now was a Normal type Pokémon with a very fragile body, but that changed as soon as poison started to affect its own mind, massively enhancing the influence it had on other Pokémon and people, and even the environment. The Poison type of Bulbasaur was limiting its dormant powers, and with its poison-producing seed removed from its body a new flower started blooming, filled with weak magical powers related to the Fairy type. After Bulbasaur gained the Fairy type, it also developed some sort of psychic powers related to the way poison was working against its brain cells, eventually developing a mental resistance to the toxins of its own previous seed and becoming a Fairy-Psychic Pokémon.
There you have the first three 
As soon as I get the others done I’ll write them here XD enjoy!
Edit: Ok, back with the two requests: Delta Ralts and Delta Scyther.
Starting with Ralts… This Pokémon was born a fast learner from a pretty normal pair of a Gardevoir and a Gallade, initially living in a very joyful way with its siblings. But this specific Ralts had a brain a lot more developed than the rest of the family, including its own parents, and eventually started attempting at the manipulation of an extremely powerful psychokinesis on the atomic level, something that only the black holes of mother Gardevoir would have been able to stop. In order not to kill their child and protect the other way weaker siblings, they decided to abandon this Ralts in a human building and leave it be, thinking that it would be better off alone. Apparently, the absence of the two forced this Ralts to become even more powerful, able to manipulate electricity and temperature with ease. While practicing its own powers, Ralts ultimately froze its own red horns, the source of Ralts’ ability to feel the emotions of others and to read their thoughts, powers related to the Fairy and Psychic type, while the massive amount of mental power remained, as it was too strong for anything else to stop it. The loss of the two original types contributed to the enhancement of Ralts’ own ability to manipulate energy. This even led Ralts’ own green “helmet” to get covered in constant electric bolts, to prevent others from touching it. As for the ability to manipulate temperature, Ralts itself decided not to use pyrokinesis (while it easily could), and went for cryokinesis instead, as a sort of limitation of its own powers, remembering the indirect lesson that its parents gave the Pokémon. Eventually, its body became too cold to even light a cigarette, hence the impossibility to create or manipulate fire. Being able to use psychokinesis, it is of course still able to use some Psychic type moves and even emulate Fairy moves such as Moonblast. Its parents are nowhere to be found now, but it is possible that they saw the future of their baby and left some “gifts” in a cave, in case Ralts evolved. The psychic power of Ralts itself however was in the way, so it was hard for its parents to understand whether it would have become a Gardevoir or a Gallade, leaving a modified version of their own Mega Stones for it to use, as they thought its mind would have let Ralts Mega Evolve by itself.
About Scyther… it was an old, solitary Pokémon once forced to hide in a frozen cave to escape some powerful Rhyperiors who had invaded its territory. While still pretty weakened by the frost, its pride allowed it to survive in the coldest of temperatures, even though its own scythes had become frozen and fragile, and its wings replaced by icicles, losing its already useless Flying type. Eventually, Scyther lost every inch of its mantis-based heritage, becoming an icy reptilian version of the Grim Reaper, quickly dashing in the snow and on ice to prey on Glalies, Walreins and even Avaluggs. Fighting these strong Ice type Pokémon improved its skills as a hunter and as a warrior Pokémon, eventually granting it the Fighting type. That, until a Pokémon trainer with a Metagross and a Steelix was able to catch it. The fight was fierce, but its physical prowess was nothing compared to the bulk of the two Steel type beasts, so it eventually lost the battle, even though never fleeing. During the fight, Scyther had already started developing an immense layer of ice to counter the tough shields of Steelix’s diamond-hard body, but it was the psychic powers of the Metagross that gave it the hardest of times. It is even possible that remembering the feeling of something metallic would trigger the evolution into a Scizor. Somehow, an old man who had witnessed the fierce fight of that Scyther was able to create a Mega Stone, hoping to be able to give it to that proud Scyther in its best stage.
Enjoy again
Edit: Here you go, let’s try Delta Liepard!
This Pokémon is actually the first Delta Pokémon ever created. It’s the spirit of a very ancient Liepard that used to steal food from the inhabitants of a small village that existed centuries ago back when it was still a Purrloin, living in the area where now Selene City is located. Here the original townspeople used to practice magic to make their lives easier, but it was not uncommon to punish criminals or fight troublesome Pokémon with jinxes and curses. Apparently, one specific curse was able to affect this Pokémon and make it look less cute by adding various chimeral features, in order for villagers to bust the thief more easily without a chance to forgive its annoying crimes. At one point, the Purrloin was on the brink of death because it was not able to steal food for itself anymore. When the townspeople started realizing that the Purrloin was stealing for survival and not for fun, they took care of its health and then tried to cancel out the curse, unsuccessfully. That’s when they got the idea of using magic again on it, giving Purrloin the capability to create powerful illusions to allow it to prey on food by itself. The Purrloin grew immensely grateful to the villagers and (with the tutoring of magicians) started developing magical powers by itself too, gaining the Fairy type because of its newly found pure heart. It eventually became a gentle and revered Liepard, capable of helping the villagers in need with its magic, accepted by everybody even though its appearance was not the best of things. It was basically the guardian of the city. When it died of old age, many villagers were sad and buried its body in a humble casket near a little lake that was considered a sacred place filled with positive energy, probably related to Xerneas. That energy started gathering into the Fairy type body of the Liepard, that slowly regained life and consciousness through the decades. As the time passed, the village was starting to forget their guardian Liepard, even though they still practiced magic, to the point that not even rumours of its existence trascended time. In modern times there was nothing that could ever remind the new generation of the Liepard, and even the elders couldn’t be less aware. When the Pokémon was entirely revived, gaining the Ghost type and immediately getting back its Fairy type magical powers, none of the new villagers could remember it, and the poor Liepard was seen again as a monster by everybody, an unfortunate event that led to the Pokémon hiding most of its appearance with its magic. Because of this, it eventually became famous as the monster of Selene City, usually fleeing from anybody in fear of looking terrifying.
Again, enjoy 
Edit 3: You asked for Delta Pawniard and Delta Snorunt let’s start then!
There was a pack of Pawniards in the forest north of Nasca Town that used to rule in that area without any other Pokémon being able to set foot there without getting attacked aggressively. That, until some workers with Fighting Pokémon started cutting part of the forest to build the Power Farm for the recently born town of Nasca. There were many attacks of Pawniards at first, but the brutal power of the likes of the Machamp and Conkeldurr lines, some Hitmonchans (used as living pneumatic hammers) and even some Ground Pokémon (mostly used for digging) was too much for them. Even the leader Bisharps were utterly defeated in a matter of minutes. Most of the Pawniards eventually were able to flee, while some were caught and forced to help the workers as punishment for their actions. One Pawniard was able to run away, but its steel armor and helmet were completely destroyed through powerful strikes, along with its beloved arm blades, something that had it suffer shame for a long time. Until it eventually started finding new strategies to attack. That was the day Pawniard’s training began, developing smart ways of attacking through the air. It was not able to fly, of course, but it still gained the Flying type thanks to its perseverance in practicing its air moves. After honing this new aerial skill, it then decided to power up its weak hands as a means to improve its physical power, as it was still unable to attack properly without its blades. This is where the idea of chops came along: Pawniard began emulating its own arm blades, constantly improving its chops, adding the training of its (to a certain extent) kicks to obtain some unpredictability in its fighting style. While it was not able to defend as much against various types, it did improve its offensive power, gaining the ability to break the same steel it was originally made of. All the while, its skin changed with the influence of the forest, constantly covering it in moss and dust, until it eventually turned permanently green. In order to improve even more its movements while in the air, Pawniard also decided that it would have been good to have some “help”, such as fluttering matter that it could wrap onto branches, so it started using a scarf to hang onto trees and a headband to keep its visual clean and protected from its now annoying hair (its helmet was also destroyed). After this training, it went back to the area where the Power Farm was going to be built, but was disappointed as its revenge couldn’t be completed: the Power Farm was already there, and all the workers had already gone away, returning to their houses. With no other Pokémon willing to get closer to the area because of the influence of the now disbanded Pawniard pack, the Pawniard started training again, making the Power Farm its own turf, eventually reaching a very high level by itself, waiting for its old enemies to return and have its revenge.
DELTA MEGA BISHARP HYPOTHESIS:
What’s more, apparently, one of the workers had an artificial Mega Stone that could adapt to any Pokémon and bond to it forever, allowing any Pokémon to Megaevolve through touch. The artificial Mega Stone was able to grant a sudden genetic boost of a Pokémon’s stats and an unnaturally quick growth of any latent powers lurking in the Pokémon’s genetics. This Mega Stone had been lost a long time ago and had then been broken in pieces by weather conditions. Its powers, though, had not faded away: as a matter of fact, the Pawniard, while unaware, connected with the artificial Mega Stone after stomping on it unintentionally, therefore gaining the ability to Megaevolve artificially. That is, if the Mega Stone were brought to its original state.
Now onto Snorunt… While Delta Liepard might be the first known Delta Pokémon created by the actions of humans, an even older Delta Pokémon was created by nature, through a method that is opposite to the one Delta Scyther had to go through. While eating their beloved snow on the top of the volcano that existed thousands of years ago in the same area where the Fiery Caverns are now, the volcano was on the brink of erupting, a lethal danger for Snorunts and their evolutionary lines. When it eventually did, the most powerful Glalies and Froslasses of the bunch started creating the thickest layers of ice they could do to protect their own children, but couldn’t do anything for themselves and perished as they were engulfed by magma. The thick layers of ice were melting fast, but luckily for some of the Snorunts were able to escape, while one specific Snorunt wasn’t, ultimately trapped by a petrified layer of magma, literally creating a shell all around it. The Snorunt then, in order to survive, started freezing pieces of the petrified magma to eat them, until its own freezing powers were not able to freeze chunks of stone anymore and it had to start eating the magma itself at room temperature. A Heatran that lived in that volcano at the time was moved by the Snorunt’s desire to live and decided to train its ability to resist magma. During the years, Snorunt’s ice pouch slowly turned into a fire pouch, its skin became black for the burns of Heatran’s attacks during the training sessions and its head spit open after sustaining damage from Steel attacks of the legendary Pokémon. This brought Snorunt the resemblance of a little volcano-shaped Pokémon, and the training eventually switched its ice type to a fire type. After many years protecting the volcano (a symbol of its family’s courage), generating legends among the people who lived near the volcano, the area was eventually struck by a long series of earthquakes that eventually destroyed the top of the volcano and closing its crater, creating the Fiery Caverns. Snorunt was buried in the magma and falling debris, and when the magma petrified its body would, too. Snorunt was then trapped in the petrified magma until its mind shut down, remaining a legend forever. A trainer was then able to locate its original “resting place” thanks to a weak stream of life energy sensed by Mew, teleporting the volcanic Snorunt from a timeline where it was still conscious but trapped, freeing it. It then awakened after thousands of years and, frightened by the presence of an intruder in the volcano, also regained its fighting spirit.
Edit 5: Onto Bergmite!
Although many might believe that Bergmite is literally a living chunk of ice, it is actually an artic hot-blooded reptile, able to cope with the harshest cold apparently thanks to its abnormally hot blood. The freezing breath the Pokédex talks about is actually just the way the Pokémon breathes frozen air in itself and releases it after storing it in its resilient lungs. This ability allows any Bergmite to “build” layers of ice to cover itself, creating some kind of tortoise shell. The shell is not that easy to break, as ice constantly repairs it whenever it gets a crack, but this can only happen in extremely cold areas. When a Bergmite travels to an area where the air does not allow to “grow” a shell, the ice eventually melts because of the hot blood, leaving the true form of Bergmite exposed: a land-dwelling tortoise without any kind of protection. Although usually dying because of weather conditions or after being preyed on by other Pokémon, an rare case showed a Bergmite without a protection that decided to cover itself in thick mud and emulate the old camouflage ability it could exploit in a freezing ambient using ice. This is how, after losing the Ice type, Bergmite developed its way to the Ground type first, and then the Rock type after a while. When evolving into Avalugg, the reptilian look of Bergmites gets a lot more evident, but it is usually covered up by thick layers of ice. The Bergmite that gained the Rock type instead covered itself with even more rocks after evolving, especially spiky ones, gaining a more draconic appearance. What’s more, its lungs got influenced by its hot blood, giving it an extremely hot breath. Unfortunately for it, Ice became a weakness because of the new armor, that was now able to be frozen up, leaving no chances to move for the poor Pokémon.
Delta Combee / Vespiquen A team of scientists that was inspired by the marvellous field of robotics that gave birth to the likes of Genesect and Magearna decided to start a project to create an army of Combees, originally to obtain infinite production of Combee’s honey for the foreign market. The financial aid of various enterprises interested in the project eventually led to robotic, able to auto-update Combees that needed no male counterparts to reproduce, as they were basically immortal (apart from rare cases of rusting). The scientists who collected data for the Pokédex were asked to record this robotic Pokémon as Delta Pokémon, as it was the artificial counterpart of Combee and coulnd’t get its personal Pokémon number as Magearna. The ability to “evolve” into a Vespiquen was also granted to the robotic Pokémon, that could eventually update to a new, more powerful form that could emit some kind of high-frequency “buzz” to guide the Combees during the honey gathering and even during battles. In case of danger, these Combees were secretly “improved” by the military with fire weapons such as flamethrowers and poison needles, something that the government then tried to exploit. Unfortunately for them, the experiment was shut down because all the Delta Combees, after miraculously developing a conscience, escaped from the facility, led by experimental Vespiquens that could use extremely powerful Fire type moves (albeit artificial). Even though the Delta Vespiquens were all destroyed or deactivated, most Combees reached a certain zone in the forest and decided to set their new home there.
Delta Maractus was another project regarding robotics that probably involved weapons, but it was a top-secret one with no details to discuss about.
All Budews are famous for opening their buds to release pollen in the sunlight, especially in spring and summer. Unfortunately for one, that had a very rare genetic mutation that made it allergic to light. This forced the poor baby Pokémon to hide from its main source of energy, its bud started dying out and its entire body eventually darkened until it reached black. The dead bud still covered its very fragile and light-sensitive body like a hood, while the rest of it started looking like a long cape dragging on the floor because of its original length. The only coloured part that remained was its visible purple veins on its body. Eventually adapting to pure darkness, however, the Pokémon gained night vision and then immediately discovered the energy that moonlight could offer it as replacement for sunlight. Even though the dead bud on its head never awakened again, by constantly absorbing light from the moon Budew gained certain powers that were either Dark or Fairy type. This means it was granted both types since it was a dead plant that could not produce Poison anymore (thus losing Grass and Poison types). As its size allowed it to find safe places, it decided to enter a library and then find a turf in a well hidden space, hiding from the Ghost Pokémon of the abandoned area. This place was perfect for it to rest, but it didn’t allow to grow much because the Budew could rarely go out and recharge with moonlight.
The Pokédex lists rare encounters with wild Delta Roselias and Roserades too, describing them as night-loving dancers with fans. As it turned out, the “fans” were actually petals belonging to their previous rose-shaped hands, many of which died out, while some adapted to the darkness, becoming moonlight-absorbing petals. With the Fairy type energy they could absorb from the moon, these petals gained power and eventually became able to produce gales.
Edit uh lost the count XD:
You asked me for Delta Koffing so let’s try
Koffings are known for the explosive and poisonous gas they produce and store inside of their round body: apparently, some experiments were done on some Koffings to grant them the ability to discharge electric currents, so that their Poison type would also be amplified with the Electric type (since Koffing levitates). The experiment focused on the transformation of those gases into plasma, a very good conductor, at first… but at a certain point the Koffings lost the ability to create poisonous gas and started “sweating”, somehow creating very dense cumulonimbus-like clouds in their own bodies, a strange phenomenon that eventually gave them the ability to generate lightning. As the body of a Koffing was a natural insulator, the discharges of electric currents didn’t kill any of the experimental subjects. That’s when the tattoo of the Raijin’s tomoe was printed on the Koffings, overwriting its natural “toxic danger spot”. The body of each Koffing also lost the natural poison-induced purple colour, gaining a yellow-ish shade (apparently its natural colour). Many of the Koffings were not capable of exploiting their new powers at first, while one of them could manage to find new ways to improve its other abilities, such as flight. After losing the ability to explode, this Koffing started using its various protrusions to boost its own speed by shooting gas out of them, eventually gaining the Flying type and losing with time the ability to float by itself, as it was not needed anymore. It was then caught by a passionate collector of rare Pokémon.
Edit ??: Delta Scraggy (OMG)
The fact that grass would start growing all over the body of a Scraggy might seem impossible, but that is exactly what happened to one of them because of certain unknown pathogenic bacteria, while the poor Pokémon was hunting in a forest. Along with the sudden deterioration of its once perfectly fine immune system, extinguishing its Fighting type and giving it a weakness to the Poison type, the spread of this vegetable-like bacterium started developing a certain type of photosynthesis that benefitted its own life energy, eventually killing its dependence from darkness. This is when the Pokémon lost the Dark type as well, gaining a pure Grass type. Exploiting its new “bacterial vegetation”, the Scraggy started attacking through those, but never forgot its classic Headbutt move, to the point that the moss on its head started getting thicker and thicker along with its skull, allowing it to use even stronger headbutts.
Spooky edit: Delta Wooper
Apparently, a Wooper was wandering around in a forest during Halloween, when it encountered a Halloween party of various Ghost-type trainers. Since the Wooper is known to always smile, no matter the situation, the trainers started playing with it and their Pokémon challenge it to a jumpscare contest. Most of the Ghost Pokémon failed and started sulking in disappointment, while a Trevenant and a Gourgeist never stopped trying. At a certain point, Trevenant decided to use its special move, Forest’s Curse, making Wooper a Water-Ground-Grass type. As Wooper was literally having fun because of the curse, Trevenant increased the power of its attack. The curse started spreading more and more in its body for this reason, absorbing both the mud of its skin and its acquatic abilities, therefore making Wooper a pure Grass type. At this point, Wooper was still smiling but a bit less, because of the surprise of losing its original natures. That’s when Gourgeist couldn’t stand the smile anymore and used various times its Will-O-Wisp on the Grass Wooper to actually hurt it and make it sad. When it did, the ghostly fire of the attack added up to Trevenant’s Curse and got absorbed by it, granting Wooper the Fire type as well. This immediately gave it the ability to generate Fire type attacks directly from its body, that had become some kind of Wooper-shaped pouch. Being a Grass type on a curse, with unlimited vegetation regenerating from the ashes of the ghostly fire, the Pokémon became hotter and hotter, and then started laughing because heat apparently was tickling for the Pokémon. At this point, Trevenant and Gourgeist gave up and everybody started laughing with the Wooper, who was then painted by the trainers like a Halloween pumpkin spirit, thinking that the paint would go away with its Water-Ground type, that allowed it to be covered in mud. The fact that it was now a Grass-Fire type made the paint never go away, literally leaving the Pokémon looking like a Grass Ghost type. Every Halloween, this strange Wooper goes scaring Pokémon and humans alike, only to then cover them in stolen candies, in memory of that event.
Toxic edit: Delta Shinx
After the experiments on the robotic Combee were shut down because of a sudden escape of the subjects, a project to find them without harming them was brought to life: the Delta Shinx project. In this case, after the poor Pokémon were implanted Lucario’s DNA to help develop the Steel type, the scientists recreated the same poisonous weapons of the Combees and installed them on these now cyborg-looking Shinxes. After the Steel type cells absorbed the Electric type of the Pokémon to generate a certain compatibility with robotic armors, all the Shinxes were given artificial poison-producing glands that helped them develop Poison-type powers, helpful to give the Pokémon some means of offensive power (after losing their Electric powers) along with developing immunities in case the Combees attacked with poison needles. Not every Shinx was able to survive these conditions, and some of them were returned to their original form with certain machines that enhanced the electric stimulation of cells, returning free. The rest of the experiment was about giving the remaining ones certain gadgets like zoom-improved sight and even X-ray radars, that they could exploit without need for batteries thanks to their old affinity with the Electric type and to the fact that the Steel type cells had absorbed the ability to discharge through their own fur. Then, a battle between the Combees and the Shinxes had started near the Combee forest, and although the Shinxes weren’t meant to harm the robotic bugs, they were utterly defeated with Fire attacks from the Combee’s reactors. The devastation was so great that the Shinxes scattered all around the areas, most of them disappearing from the human-acknowledged areas and never returning. One of them was able to hide in a hardly accessible and very dark spot in Murk forest, near the hideout of a very reclusive man.
