How about
:
1. Budgie: I guess you might call them proto-metal.
2. Blue Oyster Cult: close enough to metal for me, and awesome.
3. St. Vitus: doooom from the 80's
; Candlemass started back then as well.
4. Kreator: I don't think anyone else has mentioned this thrash band that started back in the 80's.
5. I will second someone else's suggestion of Cirith Ungol.