For me personally some of my favorites (most memorable) are:

Hitman 2: Silent Assassin main title (and first half of the OST)

Divinity Original Sin 2 main title

Original vanilla WoW main title music

Sanctuary from Borderland 3’s OST

BFG Division from DOOM

Pretty much the entire Skyrim soundtrack

Most of the Witcher 3 soundtrack. My favorite is probably On the Champs-Désolés, which is from the Blood and Wine expansion.

I listen to "Carmeaty Burana" from Super Meat Boy all the time.

https://youtu.be/CRiyU6JZ3LE

Pretty much any Danny Baranowsky is gonna be good.

Deep Stone Lullaby fro the Deep Stone Crypt raid in Destiny 2.

It’s an absolutely beautiful piece of music, but so much impactful more when tied to where it appears in the raid as you battle your way across the underside of the space station, all of the other sounds muffled by the vacuum of space.

I don’t know who the guy is, but this video of DrLupo playing it with an orchestra playing the track live while he does is pretty damned amazing.

Underwater theme from donkey Kong country

Really really obscure but I could never take this song off my head, from A Thousand Arms, psx game. Game was a goor jrpg.

Ace Combat

Skyrim was pretty epic… even the “wandering around” music was perfect.

But my #1 is Still Alive (closing theme song to Portal).

Chrono Cross ftw

Mega Man 3 on guitar is fantastic: https://youtu.be/9__sJWMXjE0

Not exactly answering the question, but hearing every generational rendition of Proof of a Hero throughout the Monster Hunter games still gives me the feels

For me definitively the soundtrack of Boneworks (which is also the best VR game I know). Especially its main theme ("Bone Theme") and "Who am I"

Some more awesome OSTs in no particular order: Minecraft, Banjo-Kazooie / Banjo Tooie, Witcher 3, Risk of Rain 2

Wingspan. I have the Vinyl OST.

Monument Valley is quite nice too.

There is a reason Touhou has two fandoms, one for its games and the other for its music. The music alone saved it from being another Oregon Trail and eventually got it its own anime.

I'm going to go for a bit of a deeper cut and say Mad Rat Dead. They took a genre which relies so heavily on the strength of its music (rhythm platformer), and produced a soundtrack where literally every song is a banger, and produced some great emotional moments as well--the transition from Cottage House to Kind of Hope and Neuchatel still makes me choke up just thinking about it.

Tony Hawk was a big one. The EA sports games always have some bangers that get stuck in your head. One of my favorite video game moments, though, was bombing the tobacco fields to Bomba Estereo's "Fuego", in Far Cry 6. They employed music well, throughout, but that moment was really enveloping.

I'm a big fan of the Offworld Trading Company OST.

https://youtube.com/playlist?list=OLAK5uy_mKUh4ny0EVAbJNHR9Bd69cS6I49VdHric

It’s not better than Tetris I’ll admit. But I’ve always had a soft spot for the Mass Effect soundtrack.

Haven't seen it mentioned, but, Spiritfarer

Hands down, DOOM Eternal

Mario 2.

https://youtu.be/yBISfv-6hfo

Hughe fan of the low roar songs in death stranding

Samurai Shodown series has an amazing soundtrack. A mix of traditional Japnese sound, rock music, chaotic jazz, and ambient sound that barely resembles a song. The ending of 3 is my ultimate 'get pumped' song:

https://youtu.be/smKr282S8-I

Star control 2 was the absolute best imo

https://www.youtube.com/watch?v=wqAYMZSOQao

My pick for best chiptune track

Modern Warfare 2 (2009)

Left 4 Dead

Warcraft classic - TBC - WOTLK - Cataclysm

They are Billions

Your reality is amazing

Castlevania, Zelda and Silent Hill (though I'd say all first 3) mentioned so I'm gonna say Alundra. Sure it's very Zelda/JRPG, but that game had some amazing music that just sticks with you.

Also a little tongue in cheek, but Adventures of Lolo. I'm not sure if there's just one song throughout the trilogy, but it sure feels like it. Weirdly it doesn't bother you. It's like a hypnosis that just makes you play one more level. One more try. Kind of like the Tetris soundtrack, but it never gets old.

I am personally in love with Far Cry 5's soundtrack.

Shadowrun for Sega Genesis

Unorthodox opinion here but Wasteland 3, the first time the Battle Hymn of the Republic played over a fight was incredible.

Diablo 1 - Tristram Theme

Ys

The theme song of Locoroco. Though the lyrics are in a made-up language, I can feel the desire for world peace in this song.