Oberer TotpunktObituaryObreroObscenityObscuraObscurityObsidianObszön GeschöpfObtestOcean ChiefOceandriveOceansizeOctober FallsOdiumOdraedirOdroerirOdysseaOffspring, TheOhmOhrenfeindtOkiesonOkkervil RiverOld Mans ChildOliva's Pain, JonOmenOmnium GatherumOn The FloorOn The RiseOnce HumanOne For The TeamOne Morning LeftOnheilOnkel TomOnwardOomph!OpethOrangoOratorioOrbeOrdeal, TheOrden OganOrder, TheOrdo InferusOresund Space CollectiveOrford, MartinOrgasmodemonOrion RidersOrkanOrkanOrphaned LandOsbourne, OzzyOsibisaOskerOST+FRONTOut and LoudOut Of SeasonOutlieOv HellOverkillOvermasterOwens, Tim "Ripper"OxydationOzric Tentacles