A few ideas

General Discussion Suggestions
1

A held item series that either adds a third type to the holder (that Trick-or-Treat/Forest’s Curse could override) or changes a Pokemon’s type to a pure type that varies by item (like Soak/Dragonify).

A held item that acts as Rock Head

A held item that acts as Drizzle/Sand Stream/Drought/Noctem/Snow Warning (or summons a random weather effect)

A held item that negates the holder’s ability

A held item that acts as Flame Body/Static/Effect Spore

A held item that acts as Water Veil/Magma Armor/Limber/Insomnia/Immunity

A held item that acts as Guts/Flare Boost/Toxic Boost

A held item that boosts the power of a certain type of move ( > Charcoal, etc.) if all pokemon in the team share the corresponding type

Will chain fishing be a thing?

Are horde encounters/triple battles/rotation battles/sky battles a viable addition?

2

All these item abilities render abilities of certain pokemon useless… -_- and from a competitive perspective, it will BREAK the metagame with these abilities. Imagine a Slaking with the ability negate item.

Just voicing my opinion.

3

What I would really like to see is a move or an ability that negates Mega Evolution.

If it’s a move, it should act like Taunt and be a Status move.

If it’s an ability, it should act like Mold Breaker.