I'm gonna assume that since this is in general it's across all media and go from there. But it's gonna plural because I can't pick just one. So in no particular order:
1. Ash Williams. The OG snarky asshole with a boomstick and a chainsaw for a hand. He's a memorable character and I love how he went from a rando worker on vacation with his friends to a dimension hopping reluctant hero fighting against hell with ingenuity and lots of buckshot. Characters like him really affected my humor and helped me develop my snark.
2. Jill Valentine. Stop doing my girl dirty Capcom. Give her a sequel already. RE2 was my first intro to games, but RE3 was the one that scared me shitless and then here comes Jill fighting the undead and biological abominations in a tube top and mini skirt. She may have started out as a schlocky B-movie type heroine, but she did the job and is my favorite Resident Evil character. Besides, she can get a lever action rifle and do the cool one handed reload move if you play on normal mode. Now if only Capcom would give her another game or give us the damn clock tower and the Dead Factory in the remake.
3. Maybe a bit lesser known, but it shouldn't be. So I'm gonna plug
Henchman Story. It's a comedy visual novel made by one of the guys who worked on DBZ Abridged. But the character in question I'm gonna have to put spoilers on because she's kinda spoiler heavy and you should get the game yourself if visual novels are your thing. So actual number 3:
Shining Nova. AKA Victoria Vasquez. AKA at least 12 aliases because she takes the superhero secret identity thing really seriously and probably isn't good with people and actually keeps the nametag with her fake undercover name on her chest to remember it as a result. At first glance she seems like an Iron Man expy, but she establishes herself as being a pretty down to earth and snarky woman with a strong sense of justice. She's a dork who likes fan-fic and hams up her acting to overcompensate but also uses that against her enemies to catch them off guard. Plus she can have a pseudo "enemies to lovers" and "love redeems" situation with the protagonist and I love that shit. She pretty wholesome too. Special mention to side character Miss Dynamo and her eternal quest to put protagonist Stan into garbage cans and fight against the tyranny of sleeves. She cool though.