Order Of Death

Australia

Order Of The Cloven Eye

unknown

Order Of The Death's Head

USA

Order Of The Divine Light

unknown

Order Of Theta

United-Kingdom

Orderless Evil Productions

Sweden

Ordine Della Luce Perpetua Productions

unknown

Ordo Decimus Peccatum

France

Ordo Draconian Black Label

Brazil

Ordo Dracul Records

Mexico

Ordo Kaos Producoes

Brazil

Ordo MCM

Italy

Ordo Obscuri Domini

Italy

Ordo Paganus

Brazil

Ordo Pestilentia

United-Kingdom

Ordogbeltz Records

unknown

Ordovician Records

USA

Orejon Records

unknown

Orexis Of Death

unknown

Orfeo

Uruguay

Orfeo-Lab

unknown

Orfice Agency

unknown

Org Records

United-Kingdom

Organic Industries

Germany

Organic Records

USA

Organik

Switzerland

Organized Crime Records

USA

Organopexic Gorenoise Records

Spain

Orgasmatron Records

Israel

Orgen Latem

Ecuador

Orgias Distro

Brazil

Orginlis Records

USA

Orgone Box Records

Finland

Oriana Music

Ukraine

Oriental Noise Records

Japan

Oriffs

France

Original Master Series

unknown

Original Music

unknown

Original Records

unknown

Original Sound Recordings

unknown

Original Sounds

unknown

Origo Sound

Norway

Oriole

United-Kingdom

Orion Metal Records

Chile

Orion Music Entertainment

Argentina

Orion Productions (POR)

Portugal

Orion Productions (USA)

USA

Orion Records

Ecuador

ORK Records

United-Kingdom

Orkestral Promenade Productions

Greece

Orko Productions

Australia

Orkus

Germany

Ormeyngel Records

Norway

Orobas Records

USA

Orochi Records

Japan

Orofarne Music

Portugal

Orphaned Records

USA

Orpheum Records

USA

Orpheus Records

USA

Orphic Mountain Production

Russia

Orquestra De Muerte

unknown

Orthodox Productions

Russia

Ortots Burdin Hotsak

Spain

Ortsid Latem

France

Oryo Productions

unknown

OS Music

Germany

Os4myfrem Alliance

Indonesia

Osaka Song Birds

Japan

Osasto-A

Finland

OSC

unknown

Oscillation Music

unknown

Oscillator Records

USA

Osculum Infame Prod

Chile

Oscuras Emanaciones Records

Chile

Oscuridad Underground Records

unknown

Osignerad

unknown

Osiris Productions

Czechia

Oskar

Poland

Oskorei Bild Und Tonkunst

Germany

Oskorei Music

Russia

Oskorei Productions

Norway

Oskun Divari

Finland

Osmium Records

Denmark

Osmose Productions

France

Osmosis Records

Canada

OSN

unknown

Oso Negro Records

Colombia

Oso Record Producciones

Chile

Osolon

Russia

Osorno

unknown

OSOSO

unknown

Ososo Records

Japan

Osso Crosso

Netherlands

Ossuaire Records

France

Ossuarium

unknown

Ossuary Industries

USA

Ossuary Records

Poland

Ost Legio Productions

Russia

Ostara

unknown

Ostatnie Tchnienie

Poland