I'm not necessarily the biggest fan of 36 (pronounced three-six), but for those who didn't know, most of his older albums are available on Bandcamp for free. Not my personal favorite in his discography, but Lithea is probably the best known and most critically acclaimed of his works.
The one-man raw black metal band Ildjarn ironically put out three gorgeous ambient releases. The latter two are a collaboration with Nidhogg. This is about three and a half hours of music. I actually haven't listened to Landscapes in a long time, but Hardangervidda is quite special.