The composer for Super Meat Boy has done lots of great tracks for Binding of Isaac and Crypt of the Necrodancer too (Danny Baranowsky)
Enter the Gungeon - Abbey or Die
Enter the Gungeon - Behold the Boss Eater
Enter the Gungeon - Boss Battle Beating
Metal Gear solid theme
Nine Sols - Collage
Hades soundtrack (all of it) + if you search for the composer (Darren Korb) then you'll find loads more great soundtracks he's done (notably for Bastion).
Hollow Knight soundtrack (all of it + the piano cover version)
Street Fighter 6 - Viator (theme for Ryu + there's a real cool metal cover that is on YouTube by an indie metal band)
Wipeout HD soundtrack (all of it)
Super Hexagon (all 3 tracks)
Hotline Miami soundtrack
Dead Cells
Lots of people have rightly mentioned FTL
Frank Kelpacki has done tons of great soundtracks across the whole Command and Conquer series and it's worth searching through.
If you're into chip tunes, then it is also worth checking out Streets of Rage 2 soundtrack.
In case you haven't noticed, I'm really into video game instrumentals. If anyone else is interested, there's a great podcast called Sound of Gaming by BBC radio 3 that is worth going through the back catalogue of episodes.
I've been playing so many soundtracks for my background music at work. Of course, nostalgia makes some songs slap harder than they deserve to, so your results may vary, but some of my favorites have been:
Mega Man series
Warcraft (I'm especially fond of Warcraft 2 songs)
Donkey Kong Country series
Variety lists (one hit wonders from games you nearly forgot)
Spotify has a lot of video game playlists, and even some covers in different styles. Right now we're listening to metal versions of classic games.
If you like prog metal and hard rock, I've yet to find a better soundtrack than Guilty Gear XX. The fan favorite is "Holy Orders (Be Just or Be Dead)", but for my money, the best songs on the soundtrack are "Existence" and "Awe of She".
I have listened to Rimworld, Disco Elysium, and EVE Online's soundtrack while working. Though it's probably my emotional attachment to EVE more than anything lol
Doesn't look like anyone listed the Ori soundtracks by Gareth Coker yet, they're amazing. Also can't go wrong with WoW if you're looking for more classic fantasy style.
Persona 3/4/5 (not all tracks are instrumentals, but most of them are and they are straight bangers)
Katana Zero
Danganronpa 1, 2, V3
Silent Hill 1, 2, 3 (all I can vouch for, but I hear the later games still have banging soundtracks)
Crosscode
Kingdom Hearts 1/2
Nier Automata
Minecraft
Donkey Kong Country 1/2
VA-11 HALL-A
Catherine Full Body
Deadbolt
Risk of Rain 1/2
Some of these you'd have to sift through, like Silent Hill is one part industrial creepy noise, and one part absolutely incredible hip hop and rock
Overall, Surviving Mars might be my favorite work soundtrack. Assorted tracks from Stellaris plus the Age of Wonders and Civilization series are also good. Something about the soundtracks in 4X games and games like them always puts me in a productive mood while not making me emotional and thus distracted like RPG soundtracks can sometimes.
Since you like FF, I'd suggest looking into Uematsu's other works as well, especially Lost Odyssey. For similar ones in the genre, there's also Yasunori Mitsuda's work in the Chrono and Xeno series.
starfield the game is divisive to say the least, but i cant imagine anyone would talk bad about the soundtrack. inon zur's best work so far, and the death metal songs in there are fucking awesome too
Subnautica has a long and beautiful OST. It's been a long-time favorite of mine, and just a great instrumental jam to fuel my creativity lately. Stardew has my other favorite game soundtrack!
I would suggest "quake 2", it's rock /metal and put me in a good mood when I work.
Now if you like instrumental metal, it's no game music, but I would suggest Aephenemer (their official instrumental playlist is on YouTube).
Can't go wrong with pretty much any pre-Skyward Sword Zelda. SS itself also has Ballad of the Goddess, which was good, but I can't remember any other tunes from it or BOTW that aren't just reprises of tracks from previous games.
I prefer Sci-fi background noise so Surviving Mars is my favorite. Mass Effect is ok but I find it gets a little too cinematic and bombastic at times. FTL and Into The Breach, or really anything by Ben Prunty is good too
My favorite soundtrack ever, of course, is that of The Secret of Monkey Island (MT-32) by Michael Land. A lot of nostalgia there.
I also very much like the soundtrack to Dune by Stephane Picq. There's an edition that combines the Adlib, Adlib Gold, and MT-32 versions which is "chef's kiss". Alternatively, I can recommend the Space Opera edition.
Strike Commander by Nenad Vugrinec on MT-32 is also great.
For chiptunes, I really liked Penny Arcade's On the Rain-Slick Precipice of Darkness 3 by Alex Mauer.
Or, for a real classic, Earthbound by Keiichi Suzuki and Hirokazu Tanaka.
Bomb Rush Cyberfunk is a music focused game and god damn but it is funky. State of Mind and Condensed Milk are my favorites but the range is wide and excellent. No two songs really share the same style.
If you're a metalhead, Metal: Hellsinger won a bunch of best music awards with such offerings as Stygia and This Devastation. It's not instrumental, but it's worth a listen and if you like what you hear it's worth a play as well. Think if Doom was a rhythm game.
Generally speaking, all of the Persona soundtracks are also top tier ambient chill tracks, especially so if you've actually played the games and have an emotional connection to these songs like myself. Persona 5 is a little more generally upbeat but I like it the best, but P4 and P3 have plenty of low key jazzfunk. I don't have specifics to recommend here but know that all three of the P3/4/5 soundtracks come with my seal of approval. EDIT: I have specifics to recommend here. Persona 5 - Rivers in the DesertPersona 4 - The Poem for Everyone's Souls ( <- This one appears in all three games with minor differences and is close to what I expect you're actually looking for from this thread) Persona 3 - Living With Determination