Rivers of Time by L. Sprague de Camp. Starts with his classic short “A Gun for Dinosaur”, and continues with sequels he wrote later in life.
The Proteus Operation James Hogan – the cliche of “someone goes back in time to help the Nazis” done well
Guns of the South by Harry urtledove. I think this is a classic – White Supremacists help the South win the Civil War, but the SDouth doesn’t exactly like White Supremacists.
Up the Line and Hawksbill Station by Robert Silverberg.
The “CrossTime Engineer” Stories by Frankowski
Heinlein’s classic short stories “All You Zombies” and “By His Boostraps”. I think Bootstraps is the ultimate time-travel story
The Man Who Folded Himself by David Gerrold. He consciously tried to pack every time travel cliche he could into this one. Gerrold also wrote a dinosaur-hunting time travel story. I forget the name, but it’s the bloodiest onme I ever read.
“The Theory and Practice of Time Travel” by Larry Niven (In All the Myriad Ways)
“Language for Time Travelers” by L. Sprague de Camp.
And, my all-time favorite:
Lest Darkness Fall by L. Sprague de Camp. Martin Padway accientally gets sent back in time. He tries to prevent the Fall of Rome.