From beginning to now for systems I own or have owned. Just a few or more favorites for each.
Atari 2600: Adventure
Atari 7800: Uh...maybe Robotron 2084
NES: Legend of Zelda and Zelda II, Dragon Warrior III and IV, Tecmo Super Bowl, Faxanadu, Castlevania III, Super Mario 2 and 3, Bionic Commando, The Guardian Legend, Kirby's Adventure
Computers in general: Doom II
Genesis (didn't own it, but a friend did in college AND I did buy Sonic's Ultimate Genesis Collection for the 360): Sonic the Hedgehog (all four on this system), Phantasy Star IV
SNES: Zelda: Link to the Past, Chrono Trigger, Final Fantasy III (sixth one, really; but only third ported to America), Super Mario World and Yoshi's Island, Super Mario RPG, Earthbound
PlayStation: Alundra (best Zelda-clone I've played), Castlevania: Symphony of the Night, Spyro the Dragon trilogy, Final Fantasy VII, Star Ocean: The Second Story, Medal of Honor, Silent Hill
PlayStation 2: Dragon Quest VIII, GTA: San Andreas, NCAA Football 06, Silent Hill 2, Resident Evil 4
XBox 360: Borderlands 2, Skyrim, Dark Souls, Dark Souls 2, GTA V, Mass Effect Trilogy, Rayman Legends and Origins, Trials Evolution
3DS/DS (since the 3DS is backwards compatible with the DS): Super Mario 3D Land, Legend of Zelda: Link Between Worlds and Ocarina of Time 3D
PlayStation 4: Assassin's Creed stuff (mainly played the remastered ones from the past generation), Bloodborne, Elden Ring, Hollow Knight, Immortals Fenyx Rising, Trials Rising, Witcher 3, Yakuza 0