I also got into a lot of the stranger characters, none of whom have their own title anymore I'm sure- guys like Nomad (getting into Punisher style shootouts with a baby on his back!)
I have to say that when the Scarlet Witch declared "no more mutants" I do think Marvel knew what they were doing. The whole idea that every other superhero was a mutant was just a little dull IMO. Can't be bothered to come up with a decent back story? Just say they're a mutant.
non-powered (Hawkeye), Aliens (Captain Marvel), augmented (Black Widow), robot aliens (The Vision)...
PS2: One else to rule out, Illyana Nikolievna Rasputina, AKA Magik (also Colossus' sister), she got her powers from Limbo