Sure I've missed something important but these are the first 25 favourite games that came to mind. Mix of childhood memories and recent bangers. Just one game per franchise, otherwise there'd be a lot more Professor Layton and Ace Attorney on this chart.
List transcription
The Curse of Monkey Island
Deadly Rooms of Death
Devotionalia
Dungeon Keeper 2
F-Zero X
Filament
Final Fantasy Mystic Quest
Ghost Trick
Grand Theft Auto: Vice City
The Great Ace Attorney Chronicles
Kingdom Hearts
The Legend of Zelda: A Link to the Past
My First Amazing World Explorer
Professor Layton and the Unwound Future
Ratchet & Clank
RollerCoaster Tycoon
Sam & Max Hit the Road
Secret of Evermore
SimCity 2000
Spider and Web
Splatoon 3
Super Mario Odyssey
Theme Hospital
Timesplitters 2
Tunic