The X-(wo)men(only mutants here and regular members): Professor X/Magneto/Jean Grey(basic Phoenix against Firelord only & Teen Jean's feats allowed)/Iceman/Polaris/Storm/Rogue/Rachel Summers(PF echo & Mother Askani allowed)/Cable(full powered)/X-Man/Legion(in control)/Northstar/Magik(Darkchylde)/Hope Summers/Namor/Vulcan
The Avengers: Hulk/Thor/Iron Man/Spectrum(Monica Rambeau)/Vision/Scarlet Witch(no HoM)/Quicksilver/Binary(Carol Danvers)/Genis-Vell(not insane)/Dr Strange(with the Eyes of Agammotho)/Wonder Man/Sersi/Sentry(full control)/Moondragon/Mantis/Blue marvel/Nova(Richard Rider)/Hyperion/Quasar
No prep for all the characters. Random encounter in New York city with no people. BFR allowed and there are all bloodlusted now!
NB: If you have some suggestions for missing powerful heroes in each team tell me like that I can add them to the list(I can't remember all their cast I did this for fun and at this moment so sorry and thanks for understanding) but don't remember ONLY the powerful ones not Captain America or Cyclops for request, please.