October Thorns

Progressive Death - USA

October, Embrace Her

Deathcore - USA

Octobers Fate

Symphonic Metal - USA

Octopus Triangle

Progressive Metal - USA

Ocularis

Deathcore - USA

Oculum Dei

Black Death - USA

ODA

Hard Rock - USA

Odax

Heavy Metal - USA

Odd Logic

Progressive Metal - USA

Odd Project

Metalcore - USA

Oddities

Deathcore - USA

Oddko

Industrial Electro - USA

Ode Vinter

Black Metal - USA

Oden Sun

Doom Metal - USA

Odiame

Hardcore - USA

Odin (USA)

Heavy Metal - USA

Odin's Court (USA)

Progressive Metal - USA

Odins Forest

Melodic Black - USA

Odinsgoat

Black Metal - USA

Odious Mortem

Brutal Death - USA

Odious Sanction

Deathcore - USA

Odious Spirit

Experimental Metal - USA

Odium (USA)

Heavy Metal - USA

Odium Totus

Black Metal - USA

Odrot

Sludge Doom - USA

Odyssean Passage

Technical Death - USA

Odyssey (USA-1)

Progressive Metal - USA

Odyssey (USA-2)

Thrash Metal - USA

Odyssey Dawn

Thrash Metal - USA

Odz Manouk

Black Metal - USA

Of Agony And Of Death

Black Metal - USA

Of Antiquity

Death Metal - USA

Of Creations

Metalcore - USA

Of Deities And Dust

Death Doom - USA

Of Dreams And Madness

Progressive Metal - USA

Of Echoes

Metal - USA

Of Euphoria

Post Hardcore - USA

Of Feather And Bone

Death Metal - USA

Of Flight And Failure

Metalcore - USA

Of Forsaken Divinity

Ambiant Black - USA

Of Glaciers

Hardcore - USA

Of Hatred

Thrash Death - USA

Of Ice

Thrash Metal - USA

Of Infinity

Gothic Metal - USA

Of Legends

Hardcore - USA

Of Machines

Post Hardcore - USA

Of Man And Machine

Technical Death - USA

Of Man Not Of Machine

Experimental Metal - USA

Of Mice And Men

Metalcore - USA

Of Oak

Pagan Black - USA

Of Raven And Ruins

Melodic Death - USA

Of Ruins

Deathcore - USA

Of Salt And Swine

Hardcore - USA

Of Sights And Sounds

Post Hardcore - USA

Of Silence And Salvation

Metalcore - USA

Of The Betrayer

Symphonic Death Black - USA

Of The Fallen

Black Metal - USA

Of The Son

Metalcore - USA

Of This Oak

Black Metal - USA

Of Truth

Metalcore - USA

Of Tyrants

Deathcore - USA

Of Virtue

Metalcore - USA

Of Wrath And Ruin

Progressive Metal - USA

Off (USA)

Hardcore - USA

Off Kilter

Folk Metal - USA

Off With Her Head

Hardcore - USA

Offensive (USA)

Thrash Heavy - USA

Office Of Strategic Influence

Progressive Metal - USA

Offspec

Modern Metal - USA

Ofstingan

Black Metal - USA

Ofthorns

Black Metal - USA

OG Tegnet

Black Metal - USA

Ogasawara

Black Metal - USA

Ogre (USA)

Doom Metal - USA

Ogre Upstairs

Thrash Metal - USA

Ogreish

Thrash Metal - USA

Ogressa

Stoner - USA

Oh

Metalcore - USA

Oh No The Afterlife

Progressive Metal - USA

Oh Shit They're Going To Kill Us

Crossover - USA

Oh Sweet Ransom

Screamo - USA

Oh The Blood

Post Hardcore - USA

Oh The Irony

Metalcore - USA

Oh, Destroyer

Grindcore - USA

Oh, Manhattan

Post Hardcore - USA

Oh, Redeemer

Metalcore - USA

Oh, Sleeper

Metalcore - USA

Ohm

Progressive Metal - USA

Ohmphrey

Fusion - USA

Oil

Thrash Metal - USA

Okilly Dokilly

Metal - USA

Okketaehm

Black Metal - USA

Oklahoma

Southern Rock - USA

Okosu

Death Metal - USA

Ol Sonuf

Melodic Doom - USA

Ol' Scratch

Sludge Doom - USA

Olathia

Thrash Metal - USA

OLD (USA)

Grind Death - USA

Old Coven

Thrash Black - USA

Old Crow

Stoner Doom - USA