Charizard, and it's because he gets "special treatment" from GameFreak. Greninja gets just about as much "special treatment" as Charizard, and I don't see anyone dogging on him. I like both of them by the way, they're both so cool. I just wish people weren't so poopy about it.
Also O. Palkia, Probopass, Emboar, Incineroar, Crocalor, Flamigo, Rillaboom, Garbodor, and other ones I can't think of right now.