Into Futurity, As Wells Put It

Sf takes its readers into the future. (It also takes them in every other possible spatiotemporal direction but right now I am talking about the future.)

Sf can also take its characters into their futures by:

time travel

temporal stasis

time dilation

suspended animation

longevity

at least one other (see below)

Thus, Wells' Sleeper sleeps and his Time Traveller time travels. The hero of Robert Heinlein's The Door Into Summer does both.

Poul Anderson has temporal stasis, with different technical jargons, in "Welcome" and "Time Heals" and time travel into the future in "Flight to Forever." In Anderson's The Boat Of A Million Years, a man born before Christ winds up in an indefinite future of slower than light interstellar travel simply by not dying! (He must then also benefit from time dilation but this is not evident because he does not return to Earth.)

One Other?

In Larry Niven's A World Out Of Time, Jerome Branch Corbell, dying of cancer, had his body frozen, thus killed. Despite Corbell's hopes, a frozen body cannot be revived. However, his memory DNA is extracted and injected into a brain-wiped state criminal who now thinks that he is Corbell - Corbell II. This individual refuses cloning with RNA transfer, returns to the Solar System after millions of years thanks to time dilation and suspended animation and then, in that remote future, finds a rejuvenation technology: teleport the chemicals associated with aging out of the body. The instant elsewhere is the young forever. Give us more Corbell.

I might reread more of A World Out Of Time.

"...even after the last line the feeling remains of the story still rushing on into the magic distance of the universe."

-A.E. van Vogt, quoted on p. i of Larry Niven, A World Out Of Time (New York, 1976).