I'd say Green Lantern. I'm not much of a GL reader, but from what I know, the Lanterns' basic power is only limited by their imagination. And the colour yellow, of course.
Also Superman and Batman, because their iconic status makes them ageless and immortal.
I'm joking of course, but then again Batman's had at least four Robins that I know of and he hasn't aged beyond... um... I don't know. Forty-something at best? And he doesn't even have a superhuman background.
By the way, many of the most powerful beings mentioned in this thread are not really superheroes, the Endless for example.
Also Superman and Batman, because their iconic status makes them ageless and immortal.
I'm joking of course, but then again Batman's had at least four Robins that I know of and he hasn't aged beyond... um... I don't know. Forty-something at best? And he doesn't even have a superhuman background.
By the way, many of the most powerful beings mentioned in this thread are not really superheroes, the Endless for example.