There's a lot of great music but not gonna lie, I loved the MainGame music in The Fateslayer it works with the graphics to create a real eerie and unsettling feeling. It actually gave me the chills at one point. My favorites in no particular order below. I'm including one from my game, which I did not make. Mine was made by Drexegar.
Klepsydra (Legends of Time Track 06 Level)
1000 Stars (Solar) & (End 2)
Chaos Between Realm (Track one)
Rick Starfield (Space Brigade)
Magnilo (Winter World)
The Drunk Time Traveler (Track 03 Japan)