Wait a tick. Basil, if I travel back to 1969 and I was frozen in 1967, presumably I could go visit my-frozen-self. But if I'm still frozen in 1967 how could I be unthawed in the 90s and travled back t- Oh no I've gone cross-eyed.
~ Austin Powers

Heroes who can travel through time - these heroes are often able to amass great power as a result and too have great advantages over their enemies due to advanced technologies/magic and heightened intelligence or warp time so as to restore or create alternate realities (often with themselves as a savior and/or a ruler) and restoring and preserving the space-time continuum.

NOTE: Not to be confused with Heroes from the past who are heroes who disappeared in the past and later came back to resume their heroics.

Good examples Of Time-Travellers Are: Agent J, Kyle Reese, Marty McFly and Wolverine (X-Men Movies).