Panzer Dragoon is probably my pick for the Saturn. Starfox was a huge deal back then and PD was kinda like Sega's answer to it, much as Sonic was their answer to Mario.

Shenmue for Dreamcast for me as well.

Man I miss Sega sometimes, they really had a style all their own, in both hardware and software.

Not a big Fan of saturn myself, don't know the games that made the console special.

Shenmue was such big deal for Dreamcast, the game was far ahead of anything at that time.

For me, in addition to Panzer Dragoon, the sequel Zwei, Nights into Dreams, Burning Rangers, and Radiant Silvergun were the main games that stand out on Saturn to me. I have a soft spot for the console, it may not have sold well but it has its own unique flavour.

And yeah Shenmue was mindblowing for its time. Soul Calibur also stands out as an iconic Dreamcast showcase.

GameBoy: Wario Land

GameBoy Color: Pokemon Gold and Silver

GameBoy Advance: Advance Wars

Nintendo DS: WarioWare Touched

Nintendo 3DS: Luigi's Mansion Dark Moon

Only going to list platforms I currently own.

PC: StarCraft.

OG Xbox: Halo CE.
Xbox 360: Halo 3.
Xbox One: Halo 5.
Xbox Series X: Halo Infinite.

Playstation 1: Final Fantasy 8.
Playstation 2: Grand Theft Auto Vice City.
Playstation 3: Uncharted.
Playstation 4: Ghost of Tsushima.
Playstation 5: Horizon: Forbidden West.

Nintendo Entertainment System: Mario Bros 3.
Super Nintendo: Super Metroid.
Nintendo 64: Perfect Dark.
Gamecube: Metroid Prime.
WiiU: Mario Kart 8.
Switch: Mario Kart 8.
Gameboy: Pokemon Red/Blue.
Gameboy Color: Zelda: Links Awakening.
Nintendo 3DS: Samus Returns.

Atari 2600: Space Invaders.

Sega Megadrive: Sonic 3 & Knuckles.

Atari 2600 - E.T
NES - SMB 1
Genesis - Sonic 2
SNES - DKC
Sega CD - Night Trap
PS1 - Syphon Filter
Saturn - Nights into Dreams
N64 - OOT
Dreamcast - Code Veronica
PS2 - GTA3
Xbox - Halo 2
Gamecube - Animal Crossing
Xbox 2 - Halo 3
PS3 - Uncharted 2
Wii - Wii Sports
Wii U - Nintendoland
PS4 - Knack
Xbox 3 - COD Ghosts
Switch - Breath of the Wild.

PS1: Final Fantasy VII (or 8,9 their all great)
PS2: Final Fantasy X (too many great rpgs to count tho)
PS4: Persona 5 / Last of US remastered
Snes: Super Mario World / Super Mario RPG / Secret of Mana
Gamecube: Zelda - Wind Waker / Paper Mario TTYD
Wii: Mario Galaxy I+II, Xenoblade Chronicles
WiiU: Zelda Breath of the wild (apart from zelda, kinda lackluster game lib. looking back today)

3DS: Super Mario 3D land, Bravely default + second,...
PSP: FF tactics - war of the lions, Patapon, LocoRoco , Jeanne d'Arc....
Vita: Legend of Heroes + Atelier games. Persona 4 golden
Switch: Mario Oddessey, but alot of great rpgs on it as well.

If I absolutely had to choose one for Switch I suppose I'd go with either Mario Odyssey as one of the first and best true exclusives, or Monster Hunter Rise as it's by far my most played game on the system, and one I'd been dreaming about since the 3DS days.

Successful systems tend to be harder to nail down as they tend to have more noteworthy games.

If I absolutely had to choose one for Switch I suppose I'd go with Zelda Breath of The Wild. That game was was synonymous with swith for a while. So much so that some people went to the store saw no switch and still bought the game. It had over 100% attach rate for a bit.

Sega Master System: Alex Kidd

Sega Genesis: Sonic the Hedgehog

Sega Saturn: Panzer Dragoon

Sega Dreamcast: Sonic Adventure