One power I’ve always entertained is the ability to slow the passage of time linearly to the level of danger you’re in.
You can’t move much faster than the average human, and just because you can see something coming it doesn’t mean you can avoid it (though with time, your eyes will eventually train your muscles to reflex appropriately).
The ultimate killer ending of such a superhero would be an unwinnable situation (e.g. Comet coming to obliterate Earth) and all our hero will see is time slow down and down and down until the point where the catastrophe is about to occur, but (for them) never does.