I don't think there's room enough on the boards for me to list them all.

Batman - outside of Adam West, I just don't like anything about him or almost all of his villains (Catwoman might be the only one I can stand)
Squirrel Girl - pretty much everything about her grates on every nerve I have (animal-themed, squirrel theme, deus ex machina beat everybody power, annoying "cuteness", absurd humour, 4th wall breaking)
Sentry - too powerful; insane; uninteresting
Moon Girl - generally, I don't like super-wunderkinds
Deadpool - I don't like mercs, plus the humour, plus the 4th wall breaking
Gwenpool - like the worst of Deadpool turned up a few notches
Venom - I tolerated as an occasional extreme Spidey villain, but never as a protagonist, not even when Flash wore the suit
Harley Quinn - too sexed up; she's a horrific villain and don't try to relabel her or make her suitable for kids
Superman - It's been very tough since I left grammar school. While I don't want him to be edgy or dark, I just can't take the boy scout-ness.
Spider-Man - I can't since the marriage ended. Until they retroactively bring the marriage back, his name is mud with me.
Wolverine - He's just not the same character after 1993 or so.

That's all I want to list for now.