Rogue
Now we all know Rogue as well as Storm, and it might look as impressive as the section above this one, but let me make this clear. Rogue. Is. A. Badass. After Storm she is probably the strongest female mutant alive (mainline Marvel), I mean power absorption is a very very useful power set and a lot better than the weaker version of power mimicking because you not only grow stronger but you also weaken your opponent without having to do anything besides touching them. It doesn't hurt that Rogue also has the powers of the first Ms. Marvel to back her up and training with some of the best hand-to-hand fighters (such as Wolverine and Storm). As I said before it may not look impressive but think about it, in a fight between Rouge and someone like Wolverine (the Badass of Marvel) and Rogue no matter what amazing martial arts he might use all Rogue needs to do is touch his skin and it is game over.