don't know about unknown, but some not as known are,
Ripping Corpse (USA)
Lethargy (USA)
Human Remains (USA)
Revenant (USA)
Nokturnel (USA)
Hellwitch (USA)
Solstice (USA)
Agretator (Sweden) (pre-Darkane)
Invocator (Denmark)
Disaffected (Portugal)
Dark Millennium (Germany)
Wings (Finland)...