I listen to this one an awful lot, and from start to finish, which is pretty rare for me when it comes to soundtracks. The song '14.3 Billion Years' still gets me even today and the games main theme is one or the more memorable bits of gaming music I've ever encountered.
Return of the Obra Dinn
Atmosphere. The music goes an awful long way to setting a games atmosphere and this soundtrack is no different. I can't necessarily listen to this on repeat like Outer Wilds, but when I do listen to it I'm immediately catapulted back to being on that damn ship.
Tearaway
This one is just disgustingly charming in a way that only a game for a Media Molecule game could be.
I think Death Stranding's use of the soundtrack was top notch. The way the music would swell up as you made it past certain points really accentuated the game.
Also Low Roar's music is just so haunting and beautiful. Rest in peace, Ryan Karazija.
Plague Tale: Requiem is one of my favorite games ever (even though some parts of the gameplay really suck) and the soundtrack is a large reason why. Every bit of it is handcrafted for very specific reasons. The composer did a playthrough on YouTube explaining each piece in context.
Been playing that recently and I agree, it's got some really lovely music. Not sure if I'd listen to it away from the game, but when you're playing and you're in that world it's really nice.
I realise I'm listening to a lot of game soundtracks, now that you are asking. Old stuff like Diablo 2 and Torchlight 2 (oh Matt Uelman, what a genius), then some sci-fi games like Mass Effect, Warframe (only the first few songs), Deep Rock Galactic. Then some RPGs like The Witcher 3 - this is so distinct and I'm instantly roaming the lands again when listening to that. Also really like Mick Gordon's Doom but have to be in the mood for that.
Honorable mention goes to Jeremy Soule and the first Guild Wars 2 soundtrack that was fantastic, but I walked away from the game and don't feel like listening anymore. I probably forgot some. Curious about what others like!
I know there's plenty that I like whilst playing the games, but the Stellaris soundtrack stands out as a beautiful suite of music in its own right. I've listened to that on headphones on the train.
The soundtrack for Bastion absolutely slaps, for whatever reason it's the perfect blend of up beat/tempo and not attention grabbing that makes for great focus music (got me thought more grad school papers/ projects than I care to admit). Risk of Rain and FTL also deserve an honorable mention here as well.