>>86832599I think it's much easier to write about characters who've been affected negatively by power seep.
But I'll still contribute...
Spiderman's benefited from the power creeps he's gotten. I mean, he's essentially the face of Marvel, so I don't think it hurts that he gets just a little bit more powerful. They always seem to revert him back to being weak though, so I guess he doesn't really count that much.
So, I'll have to say that Cyclops benefited from power creep. Originally he was not too strong, with his blasts being so weak that just demolishing a tank was considered impressive. Eventually, his optic blasts got so powerful that it could punch through mountains and pulverize Sentinels. Some people who watch only the X-men cartoons might be surprised to know that Cyke has been in numerous leadership positions, but it's not just due to the fact that he knows how to lead, but it's also because he can DEFINITELY hold his own weight.