Ommadon

Heavy Metal

9 Albums

One Machine

Thrash Metal

2 Albums

Onslaught

Thrash Metal

11 Albums

Opensight

Metal

1 Album

Ophelion

Progressive Metal

1 Album

Ophidious

Death Metal

1 Album

Opia

Gothic Metal

1 Album

Opium Lord

Sludge Metal

3 Albums

Oppress.

Black Metal

1 Album

Orange Goblin

Stoner Metal

12 Albums

Orbital Alignment

Death Metal

1 Album

Orbital Junction

Heavy Metal

2 Albums

Orme

Doom Metal

2 Albums

Orpheum

Metal

2 Albums

Oscar and the Karma

Metal

1 Album

Osiah

Deathcore

7 Albums

Ossiyan

Heavy Metal

1 Album

Our Hollow, Our Home

Metalcore

9 Albums

Our Man in the Bronze Age

Metal

4 Albums

Outback

Metal

2 Albums

Outergods

Black Metal

2 Albums

Outer Head

Doom Metal

4 Albums

Ozzy Osbourne

Heavy Metal

23 Albums

P2TEN

Progressive Metal

4 Albums