So, I know people before have posted about music that is Cthulhu mythos inspired or at least give the same feeling.
I listen to...
The Call of Cthulhu: Dark Corners of the Earth soundtrack. I think it has a great atmosphere, and since it's a from a game you can follow the tracks, and form a little story out of it in your head.
Graham Plowman (YouTube). He makes a lot of mythos inspired music, kinda like Cryo Chamber (YouTube). Although, while Cryo Chamber's music is more ambience. Graham Plowman makes compositions, so if you're more into that... here you go.
Pierre Angel's album: Cthulhu Mythos (Spotify). I don't know how to describe this one other than that it's pretty good, and also has some cool and interesting voice bits.
I would love to hear who you guys listen to (if any), that encaputre that mystical and sometimes rather dark feeling.
I don't know if you use Spotify but I have made a playlist for dark Lovecraftian atmosphere. It's great if you want to study the Bible of Cthulhu or other occult texts. It's also good for sleeping with.