Mayhem - Deathcrush
Very influential release amongst the second wave of black metal.
Demilich - Nespithe
While this album may not be incredibly popular, I believe it played an important part in shaping the genre of technical death metal.
2.2 Unpure / Infinitum Obscure / Volahn
2.13 Volahn / The Haunting Presence
4.5 Antaeus / Demoncy / Volahn