While the stats of Megas vary, their role and movesets will hardly differ except with some exceptions such as Mega Banette. Mega Kangaskhan, a Pokemon that got what I would call the biggest buff in Pokemon, doesn't seem to even need a different moveset, besides of course the huge viability of Body Slam. Otherwise I've been using the standard Fake Out and Sucker Punch priority set. Even something like Charizard X will not really need a new question, since we have physical Charizard sets on the Charizard moveset question.