Dune is one of the greats - like many others on this thread I could not read the sequels.
Foundation was originally published as a series of stories that Asimov later stitched together - one reason why some can’t get into it. It’s also quite dated for readers of today - Asimov’s galactic future lacks technology we have today. I rejected the premise of psychohistory - there are too many variables in the population of a single planet to make the future predictable to the degree specified, let alone a galaxy of different worlds. Still enjoyed the books, but have never been tempted to reread them.
1984, of course, is a classic - Huxley just underestimated the time it would take for the rats to gain power.
Tried to read Dhalgren when I was very young, couldn’t make heads or tails of it so I never finished it. I should try to read it again. Same with Olaf Stapledon’s books.
Never heard of the others.
I would add:
SF:
Pebble in the Sky - Asimov
Riverworld - Philip Jose Farmer
The Boat of a Million Years - Poul Anderson
The Mote in God’s Eye - Niven & Pournelle
Ringworld - Niven
The Robots of Dawn - Asimov
Lest Darkness Fall - L. Sprague DeCamp
The Moon Is a Harsh Mistress - Heinlein
Rendezvous with Rama - Clarke
Way Station - Clifford D. Simak
Earth Abides - George R Stewart
Nine Princes in Amber - Roger Zelazny
A Canticle for Liebowitz - Walter M. Miller
Little Fuzzy - H. Beam Piper
First Lensman - Doc Smith
After Things Fell Apart - Ron Goulart
Witch World - Andre Norton
Fantasy:
Lord of the Rings
Gormenghast - Mervyn Peake
The Eye of the World - Robert Jordan
Swords in the Mist - Fritz Leiber
The Magic of Recluse - L.E. Modesitt
Voyage of the Fox Rider - Dennis L. McKiernan
Hel’s Crucible - McKiernan
The Dragonbone Chair - Tad Williams
Arrows of the Queen - Mercedes Lackey
Conan of Cimmeria - Howard / DeCamp / Carter
Just for fun, I’d throw in 1632 by Eric Flint. (Ring of Fire)