Ollin

Country: Polska / USA
Date of establishing : 2005-11
Music genere: ambient

Omega Lithium

Country: Chorwacja / Croatia
Date of establishing : 2007
Music genere: gothic metal, industrial metal

Omnia

Country: Holandia / Holland
Date of establishing : 1996
Music genere: folk, medieval

Orange Sector

Country: Niemcy / Germany
Date of establishing : 1992
Music genere: ebm, old school ebm

Ordo Rosarius Equilibrio

Country: Szwecja / Sweden
Date of establishing : 1993-05
Music genere: apocalyptic, apocalyptic folk, dark ambient, neofolk

Organic Cage

Country: Niemcy / Germany
Date of establishing : 2002
Music genere: powernoise, rhythmic noise