One Minute Silence

Nu Metal - United-Kingdom

One More Victim (UK)

Hardcore - United-Kingdom

Onedice

Deathcore - United-Kingdom

Onlihtan

Black Metal - United-Kingdom

Onryô (UK)

Avantgardiste Black - United-Kingdom

Onryo Over October

Atmospheric Black - United-Kingdom

Onsetcold

Death Metal - United-Kingdom

Onslaught (UK)

Thrash Metal - United-Kingdom

Ontos

Black Metal - United-Kingdom

Opacus

Black Metal - United-Kingdom

Open The Skies

Screamo - United-Kingdom

Operation Cunt Destroyer

Brutal Death - United-Kingdom

Operose

Symphonic Metal - United-Kingdom

Ophelia (UK)

Melodic Death - United-Kingdom

Opinicus

Death Metal - United-Kingdom

Opium Lord

Sludge Metal - United-Kingdom

Opposing Motion

Progressive Metal - United-Kingdom

Oppress

Black Metal - United-Kingdom

Optimum Wound Profile

Industrial Metal - United-Kingdom

Opus Mortis

Black Death - United-Kingdom

Oracle (UK-1)

Melodic Heavy - United-Kingdom

Oracle (UK-2)

Metalcore - United-Kingdom

Oracles Oath

Progressive Metal - United-Kingdom

Orakai

Nu Metal - United-Kingdom

Oral (UK)

Heavy Metal - United-Kingdom

Orang-Utan

Heavy Rock - United-Kingdom

Orange Goblin

Stoner - United-Kingdom

Orbeth

Experimental Metal - United-Kingdom

Orcrypt

Ambiant Black - United-Kingdom

Order Of Tepes

Black Metal - United-Kingdom

Ordog (UK)

Black Metal - United-Kingdom

Orestea

Gothic Metal - United-Kingdom

Organ Grinder (UK)

Porno Gore Grind - United-Kingdom

Original Sin (UK)

NWOBHM - United-Kingdom

Orion (UK-1)

Black Metal - United-Kingdom

Orion (UK-2)

Thrash Metal - United-Kingdom

Orion (UK-3)

NWOBHM - United-Kingdom

Orion (UK-4)

Progressive Metal - United-Kingdom

Orpheum

Gothic Metal - United-Kingdom

Orpheus (UK)

Atmospheric Metal - United-Kingdom

Orthodox Divinity

Atmospheric Black - United-Kingdom

Osiah

Deathcore - United-Kingdom

Osiris (UK)

Power Metal - United-Kingdom

Osmium Guillotine

Heavy Metal - United-Kingdom

Osraige

Black Metal - United-Kingdom

Otheria

Symphonic Metal - United-Kingdom

Oubliette (UK)

Black Metal - United-Kingdom

Our Dying Concept

Deathcore Thrash - United-Kingdom

Our Final Hour

Post Hardcore - United-Kingdom

Our Great Adversary

Black Metal - United-Kingdom

Our Haunted Kingdom

Death Doom - United-Kingdom

Our Hollow, Our Home

Metalcore - United-Kingdom

Our Imbalance

Metalcore - United-Kingdom

Out For Blood (UK)

Deathcore - United-Kingdom

Out Of Enemies

Thrash Death - United-Kingdom

Outcry Collective

Hardcore - United-Kingdom

Outcryfire

Metalcore - United-Kingdom

Outergods

Black Metal - United-Kingdom

Outgunned

Thrash Metal - United-Kingdom

Outlast The Sun

Thrash Metal - United-Kingdom

Outlaw (UK)

Thrash Heavy - United-Kingdom

Outright Resistance

Metal - United-Kingdom

Outshined

Technical Thrash - United-Kingdom

Outside Edge

Hard FM - United-Kingdom

Outspoken Silence

Post Hardcore - United-Kingdom

Overdrive (UK)

Heavy Metal - United-Kingdom

Overgrown

Black Metal - United-Kingdom

Overland

Hard FM - United-Kingdom

Overoth

Death Metal - United-Kingdom

Overpower (UK)

Thrash Heavy - United-Kingdom

Overrider

Stoner Doom - United-Kingdom

Overthrone (UK)

Metalcore - United-Kingdom

Overthrow (UK)

Thrash Metal - United-Kingdom

Owlcrusher

Sludge Doom - United-Kingdom

Own Your Life

Hardcore - United-Kingdom

Oxyacanthous

Alternativ Death - United-Kingdom

Ozone

Hard FM - United-Kingdom

Ozric Tentacles

Alternative Metal - United-Kingdom

Ozzy Osbourne

Heavy Metal - United-Kingdom

Paedo Nanny

Grindcore - United-Kingdom

Pagan Altar

Doom Metal - United-Kingdom

Paice Ashton Lord

Jazz Metal - United-Kingdom

Pain Control

Gothic Metal - United-Kingdom

Pain Penitentiary

Grind Death - United-Kingdom

Paladin (UK)

Hard Rock - United-Kingdom

Pale Mist

Black Metal - United-Kingdom

Pale Shroud

Black Metal - United-Kingdom

Palehorse (UK)

Sludge Doom - United-Kingdom

Pali Gap

NWOBHM - United-Kingdom

Palingenesis

Black Metal - United-Kingdom

Pallas Athena

Symphonic Metal - United-Kingdom

Palm Reader

Post Hardcore - United-Kingdom

Palus somni

Black Metal - United-Kingdom

Pancrectomy

Death Grind - United-Kingdom

Pandemik

Thrash Death - United-Kingdom

Panic Cell

Thrash Heavy - United-Kingdom

Panik Attak

NWOBHM - United-Kingdom

Pantheon (UK)

Thrash Metal - United-Kingdom

Panza Division

NWOBHM - United-Kingdom

Panzerwerfer

Black Metal - United-Kingdom