Most stylised and/or 2D games, actually. The realism approach in the mainstream just ages games faster. Really, really fast.
Agreed. Many 2D games from the early 90s aged very well, while many 3D games from the 90s haven't aged particulary well at all.
Anyway, some games of the 80s and 90s that I still enjoy greatly
Phantasy Star
Wonder Boy III: The Dragon's Trap
Another World
Flashback
Agony
Super Cars II
Shadow of the Beast
Streets of Rage
Super Mario World
F-Zero
Legend of Zelda: Link to the Past
Super Metroid
Final Fantasy VI
Chrono Trigger
UFO: Enemy Unknown
Indiana Jones: Fate of the Atlantis
Day of the Tentacle
Suikoden
Suikoden II
Castlevania: Symphony of the Night
I still enjoy the original System Shock and Daggerfall a great deal too, but I wouldn't say their graphics aged well.