Love him or hate him, Wolverine is one of the most iconic heroes in Marvel's library. While his initial role in the X-Men was generally as another body to fill the roster, he slowly began to become more unique and distinct from the other mutants around him. That was in no small part due to John Byrne wanting to keep one of the few Canadian characters Marvel had at the time.
That character would grow into a rich and developed cowboy-samurai, who lives by his own code and doesn't kill unless it's absolutely necessary - or when he's blinded by rage. Until someone makes a list of every character, clone, good, henchmen and potentially cyborgs if they count, his kill count has to be somewhere around the Bubonic Plague.
As with many heroes, it wasn't until the Comics Code Authority fell that Marvel Comics could finally show how brutal Wolverine could be, letting him indulge in a bit of the ultra-violence whether his claws were cased in adamantium or otherwise.
From Old Man Logan to his own death, these are the kills that'll make you truly think twice about the Canadian Canucklehead, and whether or not the thing he's best at is actually good...