- Overcast
- Open Hand
- Oranger
- Odious Mortem
- Orion's Reign
- Onkel Zbyndas Winterrock
- Only a Mother
- Othila
- On the Rise
- Odawas
- Orion
- One Dove
- Owen Gray
- Outside
- Orange Cake Mix
- Overmountain Men
- Orlando Voorn
- Orphan Boy
- Outsmarted
- Oscar Chavez
- Okay Temiz
- Our Brother the Native
- Orphan Gypsy
- Oswald Sattler
- Ollano
- Oberon
- Os Poets
- Onelinedrawing
- On Broken Wings
- Oso
- Orquesta Nova
- Owl
- Oh Astro
- Oscar Brand
- Official Secrets Act
- Ora Nombro
- Oakenshield
- Orbit
- Oliver-Dawson Saxon
- Oakley Hall
- Odyssey Band
- Olympia
- Orquesta Broadway
- Omoreka
- Oraculum
- Odious
- Original Surfaris
- O.F.I.
- Occoult Raas
- Order of Ennead
- Oxford Collapse
- Ocean Within
- Obo Addy
- Osmosaïc
- Orange Wedge
- Otolithen
- Out of the Blue
- Olivia Gray
- Oh No Not Stereo
- On the Last Day
- Operahouse
- Obsidieth
- Optiganally Yours
- Our Anatomy
- Owen Howard
- Orfeh
- Old Lost John
- Oxes
- Om Kalsoum
- Ortolan
- Osaka Popstar
- Olaf Henning
- Oxya
- Ozone
- Owsley
- Omar Torrez
- OPA
- Omega Massif
- O.G. Spanish Fly
- Odessa
- Os Morcegos
- Oliver Von Essen
- Omyiga
- Octinomos
- Our Sleepless Forest
- Onze H30
- Oro Solido
- Orleya
- Operator
- On The Virg
