It's really hard to choose, as some games blew my mind in their respective eras. But if I had to pick a few:

NES - Punch-Out!! (Mike Tyson)
SNES - Donkey Kong Country / Starfox / F-Zero / Super Mario RPG
N64 - Super Smash Bros. / Pokémon Stadium / 007 GoldenEye
GC - Luigi's Mansion / Pikmin
Wii - Xenoblade Chronicles / Punch-Out!! / Excite Truck
Wii U - Xenoblade Chronicles X / Splatoon
Switch - Xenoblade Chronicles 3 / Fire Emblem: Three Houses / and more...

But if I had to choose just one, the game that hit me the hardest and truly changed my life at the time of its release would be Xenoblade Chronicles for the Wii. I still can't understand how my poor Wii could handle that game, it was really feeling it! and didn't know I could cry even weeks after finishing it, the emotions were still hitting me hard. Damn.

It still baffles me to this day how Nintendo can just treat Donkey Kong, the namesake of their big arcade hit that brought them into the North American market, so poorly. Remember what they did to celebrate Donkey Kong's 40th anniversary? Nothing. -_-

They really need something new to get people and themselves interested in Donkey Kong again. The Country series is epically old these days, DKC was cool and fresh and exciting 30 years ago, and the last game in the series was 10 years ago. They need something new for DK that will reinvigorate the IP and get Nintendo thinking about it again. DK was hot back in the 90s with the three DKC games and Diddy Kong Racing challenging Mario Kart for racing supremacy.

I really thought they'd put out a brand new DK (not Country) game as one of the final big games for Switch, like the big holiday title this year, but nope. Maybe such a game will be an early next gen game. But they definitely need something new for Donkey Kong. It's too bad Microsoft owns I guess like most of the rights to Diddy Kong Racing, as it'd be real cool to get a sequel to that, instead it's in IP purgatory, game can't be made without both Nintendo and Microsoft agreeing.

Donkey Kong Country... has to be it right?
So many great platformers there.

Star Fox Adventures and Punch Out for me

Either that or a full on reboot, and I mean a GOOD one this time, because Diddy Kong Racing DS was (apart from new courses and the redesign of Tiny Kong) a big disappointment.

Here's hoping the new Donkey Kong section of Super Nintendo World, and even though it's shallow the Switch version of DKC Returns, bring new interest in Donkey Kong games.

A little off topic, but for those missing Donkey Kong, I'd recommend Nikoderiko: The Magical World.

It's an excellent platformer that's a lot like DKC.

If I had to pick one game it'd be Mike Tyson's Punch Out!!  Back in the NES era, I considered it of a similar caliber to the Mario, Zelda and Metroid titles.

In general I'd say that Punch Out!!, Advance Wars and the Excite ______ series have had really great games that I thoroughly enjoyed playing.

DKC2

Perfect Dark

Mother 3

F-Zero GX