In no particular order:

Ryuichi Sakamoto (particularly Async, and his albums with Alva Noto)

Aphex Twin

Apparat (though he does also feat singers on some albums)

Four Tet

Squarepusher

Ørdrop Wolkenscheidt

MGMT

Sevish

Matt Elliott (very few sung bits)

Paco de Lucía

Guilhem Desq

Jordi Savall

Ledetraad

Bremer & McCoy

Athletic Progression

Psykovsky

Godspeed You! Black Emperor

Kettel

Secede

R mccarthy

Sungazer

999999999

Susumu Yokota

Caravan Palace

These do fall into the vg category but it's more edm / retro than "epic orchestral":

Scattle

Chris Christodoulou

Toby Fox

The Toxic Avenger

Jake Kaufman

Polyphia, The Omnific, Animals as Leaders

Little People

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.

Jade Cicada, Tipper, Spoonbill.

Opiuo, Ott and Griz are probably my favorites.

https://www.youtube.com/watch?v=hJj_4ir12-w

https://www.youtube.com/watch?v=9cjxNU0S17g

https://www.youtube.com/watch?v=OMGWXAitaK8

https://www.youtube.com/watch?v=k6pJs5wPfcw

Jon Hopkins, Boards of Canada

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

Herbie Hancock, Snarky Puppy

Shai Maestro Trio.

DJ Krush for some instrumental hip hop/trip hop.

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

Additionally, Bernth is really cool if you like guitar.

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

Carpenter Brut. Though I only really listen to the trilogy from them.

Apocalyptica. Metal on the cello. They sometimes have s guest vocalist. I like their self-titled album.

Phamie Gow. Pianist and harpist. Maybe too orchestral. I turn to the Beyond the Milky Way album oftenwhen working out studying.

Mary Lattimore. Experimental harpist. I've been enjoying her latest album, West Kensington, with guitarist Paul Sukeena.

Kelly Moran. Experimental pianist Can't recommend her album Ultraviolet enough.

Burial. For some chilled, glitchy dubstep.

The Comet is Coming. For some psych jazz.

Moderat. For some house electronica.

Uboa. For some droney, noisy, doomy metal.

George Clanton. For some synthpop vapourwave. His latest album is great.

Check out ENV -- Some of my favorite lyric-less music. There are a couple of playlists on YouTube with their albums. Firefrost is a good song to start with.

Guillaume David knocks it out of the park with every game they OST.

• https://youtu.be/RhTXyUERugQ

• https://youtu.be/aJIDqYZ7qM0

I'm a metal head, so these will be in a similar vein, though there is techno and more relaxed stuff at the end. Might add links if I remember later:

Chon, Animals as leaders, Polyphia, Plini, Syncatto, Intervals, Meganeko, Broke For Free

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

That should get you a wide variety.

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

• Tremeschin
• Parnikkapore

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

The following can be classed as instrumental, post-rock or post-metal:

• Russian Circles
• Caspian
• ISIS (the band)
• Sigur Ros
• Mogwai
• God Speed You! Black Emperor
• Blanket
• Vaudlow

Ever check out some jam bands? They all have vocals but stretch the music out in interesting ways.

moe, Umphrey’s McGee, Aqueous, Phish, etc

Onward & Upward (22:48) • Umphrey's McGee • 2017-07-23 • CEFCU Center Stage at The Landing, Peoria, Illinois https://relisten.net/umphreys/2017/07/23/onward-upward?source=67144

The Flying Luttenbachers

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

The American Dollar

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

If you like proggy stuff I'd definitely check out Arch Echo, they're incredible. If you like acoustic stuff then Rodrigo y Gabriela are also a great listen, and so is Kaki King (though I mostly only know her older stuff)

I enjoy listening to The HU. They are a Mongolian Metal/rock band. Most of their songs have lyrics, but it’s all in Mongolian so I just treat the vocals as another instrument and it may as well be instrumental to me.

First two that sprung to mind were -

Meute

And

Chinese Man

Peter Gundry, Adrian von Ziegler

HOME

Infected Mushroom

Zircon

Eskimo

Check out DJ Ugly Katz!

Disclaimer: That's one of my own projects...

Listened to these two albums today, both fantastic
https://youtu.be/5w6_D-jrt6s
https://youtu.be/2GhWimO54YE

I like to listen to synthwave when driving and I can recommend 'Rivera Rivera' and 'Inexdra' as well as 'Cartridge 1987'.

The latter has some great songs that tell a story without any words.

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.

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.