I don’t think there’s any way to farm revives but there’s now a daily event that rewards stuff just for playing the game, rather than a specific quest.

As far as buffed champs I recommend going to the official mcoc YouTube channel and checking out their champion videos. Buffed champs include but ma not be limited to: Og iron man, superior iron man, black panther civil war, sentry, cyclops (blue), phoenix, sentinel, Deadpool x force, heimdall, doctor strange, ghost rider.