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 β their Album Horse Blood is pretty good.
Perturbator β sounds like you're driving on some rainy highway at night to your cyberpunk destination
There's also Instrumental Nu Metal, for example:
Andromeda β start with their song Synthesis
MASTER BOOT RECORD β it's just riffs and booms, usually no vocals
A. Yarmak β has some nice metal remixes, for example Hydrogen from the game Hotline Miami
Then there's Dubstep and Breakbeat, for example:
The Prodigy β uses samples heavily, but also has a few tracks without spoken words
Lindsey Stirling β Dubstep and violin, interesting combination.
videogame OST [β¦] either really well known or fall into the orchestral and/or βepic music scoreβ Iβm 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.