Are there any doujin albums for the Taito Ray series? I have Ray of the Air - Absolute Cycloid and it's really good!

VGMdb is still the easiest way to find out: RayForce, RayStorm, RayCrisis

Or were you looking for recommendations? Ray isn't covered very often and usually never on its own as the central theme of an album. I do like RAY ILLUMINANT. aerophonon did a RayCrisis album, in a lavender moment, that is free on the circle's site.