Asimov's Pebble In the Sky
is set thousands of years in the future.
Poul Anderson's Mauri stories are set long after our society has passed-and they're some of the best sci-fi he wrote, IMO.
There was a comic book called Magnus:Robot Fighter set a long time from now. It was published in the sixties/seventies.
The Xmen had a mini-series about Cable's childhood set in the far future.
Heinlein's Farnham's Freehold
is set a couple thousand years from now.
The Guardians of the Galaxy(original run) comics were set in the 30th century and so is the Legion of Superheroes.
Robert Silverberg wrote The End of the Line
. Lots of it takes place in the far future.
I believe Moorcock wrote something called The Dancers at the End of Time
that took place way in the future...