Marvel is too busy shitting out boring episodes, so none of these will happen but it's fun to suggest
What if Quicksilver survived?
What if everyone in the Avengers got Iron Man Suits?
What if Hawkeye sacrificed himself?
What if Carol Danvers formed the Guardians of the Galaxy?
What if Scarlet Witch never took down the Hex?
What if Loki won the Battle of New York?
What if Nick Fury called Captain Marvel earlier?
What if the Other Half Got Snapped?
What if T'Challa became King of Wakanda in his Teens?
What if the Avengers found Thanos before he destroyed the Stones?
What if Ronan the Accuser decimated Xandar?
What if Hawkeye and Mockingbird were a couple? (Like they were in the Comics)
What if Hydra assembled the Avengers?
What if Pierce killed Nick Fury in CATWS?
What if Nebula was sent to collect the Orb instead of Gamora?