I'll put one suggestion in. I've discovered Charizard with Charizardite Y makes a good Special Sweeper, especially with Fire-type moves, since when you mega evo it, Charizard's ability changes to Drought. Drought changes the weather to sunlight, so the strategy I employ is when I have Charizard in with another Fire-type Pokemon, especially a Fire-type Tank, in Doubles or Triples, all of those Pokemon gain a good boost. It also reduces the damage your Fire-type Pokemon will receive from Water-type attacks. It did backfire on me once when an opponent used it to charge its Solar Beam and attack in the same turn. :/ Consider this:
Nature: Modest
Item: Charizardite Y
Ability: Blaze/Solar Power (Drought when Mega Evolved)
EVs: 4 Defence/252 Special Attack/252 Speed
Fire Blast
Air Slash
Hidden Power Grass/Substitute
Roost
This set is normally for a Special Sweeper w/. Life Orb, but I think it can be effectively used with Charizard's Mega Evolution. Fire Blast and Air Slash both gain STAB with Charizard. Fire Blast can gain a significant boost with Drought in effect. Hidden Power Grass will provide more coverage, but Substitute can be used to absorb some damage while Charizard is using Roost to recover some HP.