Xasthur, Nortt, maybe Blut Aus Nord, and a bit further out in various directions I'll say Portal, Aluk Todolo, Jesu, Vuyvr. Should be something in there for you, and there should be plenty of samples of stuff you haven't already heard of on the youtubes.

Blut Aus Nord, Deathspell Omega, Funeral Mist, Mayhem, Ondskapt, Watain, Darkthrone, Burzum, Altar Of Plagues, Leviathan

Might not be in the exact genre, but Opeth is nice