This is what I have so far I’m looking for a good defensive wall and good special wall that fits for my team. Also what’s a good 4th move for Mega D. Charizard? Thanks for the help!
For Charizard, honestly those three moves cover pretty much every type combo except for Bisharp and some weaker fairies, so throw on Flamethrower if you want, or maybe even Taunt/Sub if you’re planning on using the team competitively.
For your walls, you definitely need another Fighting resist since once Charizard is gone your team gets swept by Mach Punch . Clefable is great as an all around wall that complements your team nicely, and if you can run Calm Mind for extra special bulk. Skarmory is an excellent physical wall that can also cover up your Ground weakness in TTar and Drill.
I feel as if your team could use a Fairy Type. If you can get your hands on a Sylveon with its Hidden Ability, it could be both your special wall, and an extremely hard hitter. Also, maybe a Quagsire or a Swampert for your physical wall. Their minimal weaknesses and extreme bulk could come in handy. Quagsire has more bulk than Swampert, but Swampert has the ability to hit harder