Ocean Colour Scene
britpop, indie rock, rock
Oceana
emocore, metalcore, post-hardcore, screamo
Oceanlab
dance, electronic, progressive trance, trance
Oceans Ate Alaska
emocore, metal, metalcore, post-hardcore
Oceansize
alternative rock, post-rock, progressive rock
Ochre
ambient, electronic, electronica, idm
Octave One
detroit techno, electronic, house, techno
Octavia Sperati
doom metal, gothic metal, metal
October Project
progressive rock, rock, folk
Odd Crew
groove metal, metal, sludge metal
Odem
black metal, blackened death metal, death metal
Odessa
melodic hardcore, metalcore, post-punk
Odesza
ambient, chillwave, electronic, electronica
Odium
black metal, melodic death metal, symphonic black metal
Odyssey
disco, drum and bass, funk, progressive metal
Ofege
afrobeat, psychedelic rock
Off Broadway
new wave, power pop, rock
Offertorium
gothic metal, symphonic metal
Office of Future Plans
indie rock, pop, post-hardcore