I like to listen to the genres Synthwave and Dark Ambiance. Spotify is pretty good to find new music in that regard. Since you asked for artist recommendations and not genres:

Judge Bitch – their Album Horse Blood is pretty good.

Perturbator – sounds like you're driving on some rainy highway at night to your cyberpunk destination

There's also Instrumental Nu Metal, for example:

Andromeda – start with their song Synthesis

MASTER BOOT RECORD – it's just riffs and booms, usually no vocals

A. Yarmak – has some nice metal remixes, for example Hydrogen from the game Hotline Miami

Then there's Dubstep and Breakbeat, for example:

The Prodigy – uses samples heavily, but also has a few tracks without spoken words

Lindsey Stirling – Dubstep and violin, interesting combination.

videogame OST […] either really well known or fall into the orchestral and/or “epic music score” I’m not looking for

Well, there are tons of videogames and many of them don't have an orchestral/epic soundtrack, and even more of them are not very well known. I think you're limiting yourself here.

Adam Young, the guy behind Owl City has made albums under different names, including his own. One of the bands is Port Blue; he made an almost purely instrumental (only vocals are the first few seconds of the second track) album called The Airship. It feels rather experimental, but I use it to calm down. The other works are under his own name: Apollo 11, Project Excelsior, and Voyager 1.

All are well made and they tell a story through the instrumental music. Would recommend.

If I'm looking to maximize my relaxation, then it's hard to go wrong with Sleepy Fish. Chill beats all the way.

If you want acoustic guitar playing that you probably never experienced before, then check out Alan Gogoll. Love his stuff. Always nice to listen to. His song Mulberry Mouse is a favorite of mine.

Aether also has a few instrumental albums. Eshajori is a very melancholic feeling album. Gives me a lonely, empty feeling, but I love it all the same.

In a completely different direction, but you could check out The Glitch Mob. Definitely electronic, but I wouldn't say EDM.

That's all I have on my phone at the moment. Hopefully these are good starts.

vexento

Peter Gundry, Adrian von Ziegler

City of the Sun is some fantastic Latin-inspired instrumental post-rock. (That’s probably drivel, idk what genre they are).

Their cover of Young Folks is how I found them, but their self-titled album from 2020 is probably one of my favorites of the last several years. It’s a good balance of calming serenades and powerful melodies.

Hon. mention - The Samuel Jackson Five - Easily Misunderstood is another old favorite of mine. Angrier and edgier, but still haunting in its own way.

The Beastie Boys also have a couple fantastic instrumental jam albums - The In Sound From Way Out, and The Mix-Up.

Helios - Caesura and Ochre - Lemodie for electronic music. Jizue - Bookshelf and Mouse on the Keys - An Anxious Object for jazz. Auxcide - of Atoms and Stardust for chiptune. Kplecraft - L 012 for both chiptune And jazz. Flying Saucer Attack - Distant Station for space rock. Dedalus - Dedalus.

Nils Frahm, his albums are quite different from each other; here are some I like in no particular order:

• Spaces
• 7fingers
• Electric Piaon
• Streichelfisch

Elephant Sessions, Kan, Peatbog Faeries, Monster Ceilidh Band, Flook. Peatbog Faeries have a new album out now that's great, but it is their first album with some vocal samples (not with many words though). All Celtic fusion bands to a greater or lesser degree.

Bruit ≤

Kashiwa Daisuke

I'd recommend Solo by RiveR idk about the rest of their songs though I've only listened to Solo.

I haven't seen anyone mention Tempel yet. And yes, it's spelled Tempel not Temple.

The French 79 has some lyrics but is primarily electronic melodies

Lindsey Stirling? Not sure if this is up your alley, but, her music is pretty great.

Also, Two Cellos, and the Piano guys.

Its, not classical. It's all instrumental music, no singing.

Lindsey Stirling: https://www.youtube.com/watch?v=aHjpOzsQ9YI

Two Cellos: https://www.youtube.com/watch?v=uT3SBzmDxGk

Oh, and as a bonus- more of their songs then not, are pretty damn good. I can listen to them non-stop through an entire workday.

Zoe Keating https://music.zoekeating.com/album/into-the-trees

The Flying Luttenbachers

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

Look up Nox Arcana if you want something Gothic. Might be a bit too orchestral for your needs, but it's a dark version that's unlike anything I've heard.

A few more for you that I don't think I've seen mentioned: Kalaido Tycho Worakls The Cinematic Orchestra

Jade Cicada, Tipper, Spoonbill.

Well, I happen to quite like upbeat, 8-bit-style music, but here's concrete artists nonetheless:

• Tremeschin
• Parnikkapore

Marconi Union, Mord Fustang, Caravan Palace, Pkch, Siriusmo, Jacob Mann Big Band, Shubh Saran.

That should get you a wide variety.

Browsed the comments really quickly and couldn’t see that anyone had mentioned Plini, so there’s my recommendation.

I've been listening to a lot of music that is featured on the NPR shows Hearts of Space and Echos, which i highly recommend. The following artists/bands are of that type, instrumental, chill, "slow music for fast times", and all are available on Bandcamp.

Hollan Holmes

Kiasmos

Lars Leonhard

Michael Stearns

Röyksopp

Feint, Matt Large, and especially Gregory David are awesome.

Additionally, Bernth is really cool if you like guitar.

Tauk

"Times Up"

Shai Maestro Trio.

Snarky Puppy! Bill Lawrence's solo work is also good

Chief Kaya, Benzmixer, Automhate, Versa, Badphaze, Akirah, Ternion Sound, Spass, Aweminus

Detektivbyron

Its Swedish folk music with some electronica.

I only have the Hemvagen EP, and I really like half of songs, with the title track being my favorite. I think the E18 album contains all of the same songs and more.

https://youtu.be/YE2yChrT4ok

They were partly inspired by Yann Tiersen who I also really like. Perhaps you've heard the Amelie soundtrack. If not, it's excellent.

I like everything black sky giant has done. And just look at this sweet album cover: https://blackskygiant.bandcamp.com/album/planet-terror

(The opening track has some light vocal samples, but there's no lyrics or vocal parts in their stuff generally)

Edit: you can also click on the "instrumental" tag on that page and go exploring.

I've been enjoying Los Bitchos