Time Travel I’ve read and loved:
Replay by Ken Grimwood: Man travels back into his former self and relives his life multiple times, meeting a fellow replayer
The Green Futures of Tycho by Wiliam Sleator: Teen boy finds mysterious egg shaped device that allows time and tries to prevent multiple possible tragic personal futures
The Man Who Folded Himself by David Gerrold: One of the quintessential time travel novels - man inherits time travel belt and duplicates himself with it. Mostly explores his personal development, the philosophy and mechanisms of time travel, and the relationships he has with his duplicates.
TimeFall by James Kahn: Man and wife archeology professors find skull artifact that is older then recorded history, go on jungle adventure to find origin, where they discover a series of caves that lead to other time periods where they have to save the universe from coming undone. Technically third in a series, but the first two are very different and not needed at all to understand this one.
All You Zombies and By His Bootstraps (short stories) by Robert Heinlein: Classic time travel stories in which protaganist ends up being all the characters in the story including his recruiter and both is parents.
Time Travel I haven’t read but hear is good and intend to read:
Time’s Arrowby Martin Amis: A story about a Nazi doctor told entirely in reverse so that eating becomes regurgitating, killing becomes giving life, etc.
The Time Traveller’s Wife by Audrey Niffenegger: The story of a man who lives his life out of order and his romance with a woman who lives her live linearly.
A Tale of Time City by Diana Wynne Jones: Girl in WWII London is kidnapped and gets involved in a mission to save Time City, a future city which is the home base of the Time Police.
The Little Book by Selden Edwards: A sort of Forest Gump time travel story - protaganist and his family end up meeting important historical figures or playing a part in major historical events.