Wolverine is an anti-hero if one is feeling charitable, along with his tendency to only kill people who are trying to kill him (With many exceptions, but I've never particularly liked Wolverine, so I'm not bothered enough by it to care)
Deadpool was introduced as a villain, and I still view him as being one, though veering into anti-hero tendencies at times.
Amongst other things, Jason killed those who had simply committed the crime of mugging (Which is a vile and reprehensible crime, but not one that carries the death penalty as far as I know), and he did it dressed as Nightwing to ruin Dick's reputation.