Optic

Progressive Metal - USA

Opul

Progressive Metal - USA

Opus Dei (USA)

Black Metal - USA

Opus Majestic

Unblack - USA

Oracle (USA-1)

Heavy Metal - USA

Oracle (USA-2)

Progressive Power - USA

Oracle (USA-3)

Progressive Power - USA

Oracle (USA-4)

Melodic Death Black - USA

Oracle Of Fire

Atmospheric Death - USA

Oraculum (USA)

Progressive Metal - USA

Orange 9mm

Post Hardcore - USA

Orange Helicopter

Hard Rock - USA

Orange Wedge

Heavy Rock - USA

Orationem

Unblack - USA

Orator (USA)

Technical Death - USA

Orb Of Confusion

Thrash Metal - USA

Orbital Frame

Progressive Death - USA

Orbital Gate

Brutal Death - USA

Orbitas

Grindcore - USA

Orbiter (USA)

Stoner Doom - USA

Orbs

Post Hardcore - USA

Orbseven

Black Death - USA

Orcanaut

Stoner - USA

Orchid (USA-1)

Doom Metal - USA

Orchid (USA-2)

Screamo - USA

Orchid Throne

Doom Metal - USA

Orchiopexy

Grindcore - USA

ORCumentary

Folk Death - USA

Orcus (USA-1)

Death Thrash - USA

Orcus (USA-2)

Black Death - USA

Ordained

Thrash Metal - USA

Ordained Fate

Thrash Heavy - USA

Ordeals

Black Death - USA

Order 66

Thrash Death - USA

Order From Chaos

Black Death - USA

Order Of Bileth

Black Metal - USA

Order Of Darkness

Black Metal - USA

Order Of Ennead

Black Death - USA

Order Of Leviathan

Black Metal - USA

Order Of Nine

Power Metal - USA

Order Of The Jackal

Groove Metal - USA

Order Of The Nameless Ones

Black Death - USA

Order Of The Vulture

Deathcore - USA

Order Of Thelema

Doom Black - USA

Order Of Unukalhai

Doom Black - USA

Ordinance (USA)

Progressive Death - USA

Ordo Obsidium

Doom Black - USA

Ordo Tyrannis

Industrial Black - USA

Oreamnos

Death Black - USA

Orelisk

Black Metal - USA

Orenda (USA)

Deathcore - USA

Orga

Black Metal - USA

Organ

Thrash Metal - USA

Organ Dealer

Grindcore - USA

Organ Donor

Heavy Metal - USA

Organ Failure

Death Grind - USA

Organ Grinder (USA)

Avantgardiste Black - USA

Organ Harvest (USA)

Brutal Death - USA

Organ Theft

Porno Gore Grind - USA

Organ Trail

Death Grind - USA

Organism (USA)

Progressive Death - USA

Organosyde

Death Metal - USA

Orgone (USA)

Technical Death - USA

Orgy

Industrial Electro - USA

Orgy Of Carrion

Black Metal - USA

Orias

Metalcore - USA

Oriax (USA)

Death Metal - USA

Orifist

Technical Death - USA

Origin (USA)

Technical Death - USA

Origin Of Darkness

Funeral Doom - USA

Original Sin (USA-1)

Speed Heavy - USA

Original Sin (USA-2)

Hard Rock - USA

Orinoco

Metalcore - USA

Orisonata

Symphonic Metal - USA

Orlando Furioso

Hardcore - USA

Orloff

Death Metal - USA

Ormstunga

Symphonic Black - USA

Orna Annon

Thrash Heavy - USA

Ornament Of Disgrace

Death Metal - USA

Ornamentality

Death Metal - USA

Ornimental

Thrash Metal - USA

Orodruin (USA-1)

Doom Metal - USA

Orodruin (USA-2)

Black Metal - USA

Oroku Saki And The Foot

Death Grind - USA

Oros (USA)

Thrash Death - USA

Orphan (USA)

Sludge Metal - USA

Orphan Allies

Heavy Metal - USA

Orphan Project

Progressive Metal - USA

Orphaned

Crust - USA

Orphaned To Hatred

Metal - USA

Orpheus Effect

Symphonic Metal - USA

Orphonic Orchestra

Atmospheric Metal - USA

Orquesta Del Desierto

Stoner - USA

Orthodox (USA)

Hardcore - USA

Orthodox Fuzz

Stoner - USA

Orthogenesis

Progressive Death - USA

Orthopedic Cranial Encavement

Porno Gore Grind - USA

Orthrelm

Experimental Metal - USA

Orthrus

Black Death - USA

Orwell

Melodic Death - USA