I'm bored, I'm gonna come up with ideas for a What If for every MCU movie.
Iron Man - What if Tony Stark never became Iron Man (this one focuses on how the MCU changes without it's star)
Hulk - What if it was always Ruffalo I didn't watch this one
IM2: What If Justin Hammer won?
Thor: What If Loki was the one sent to Arizona?
Captain America: What If Steve never went in the Ice (I know this one was already said this is an alternate choice)
Avengers: What If Thanos came to Earth himself?
IM3: What If the real Mandarin was the antagonist?
Winter Soldier: What if Nick Fury actually died?
Thor 2: what if it was good Didn't watch this one either
GoTG: What If Carol Danvers joined the Guardians (I'm doing an alternate for this one as well)
Ultron: What if Ultron Won/What if Wanda died and Pietro lived (this can go either way, both would mostly focus on how this changes future movies)
Ant-Man: What If The Wasp survived (and Pym fell into the quantum realm)
Civil War: What If Team Cap won?
Doctor Strange: What If the Sorcerer Supreme guarded the Reality/Soul Stone?
Black Panther: What If Killmonger was raised in Wakkanda
Homecoming: What If Spiderman was on Team Cap?
Ragnarok: What If Iron Man ended up on Sakkar?
Infinity War: What If Thor died and Loki was spared?
AMatW: I don't have anything for this one
Captain Marvel: What If Carol Danvers never stopped thinking she was a Kree?
Endgame: What If the other half was Snapped (this is technically an Infinity War moment but it most affects Endgame)
FFH: What If Mysterio was legit?