Omnium Gatherum

New World Shadows	8
The Redshift	7
Grey Heavens	7
Origin	7
Slasher [EP]	7
Spirits And August Light	4
Steal The Light [EP]	4

Omnivortex

Circulate	9
Diagrams Of Consciousness	8

On Thorns I Lay

Crystal Tears

5

Once Human

The Life I Remember	9
Evolution	8
Scar Weaver	8

One Machine

The Final Cull

6

Onmyo-Za

鬼子母神

5

Onslaught

Killing Peace	8
In Search Of Sanity	6
Sounds Of Violence	6
The Force	4
Power From Hell	3

Onward

Evermoving

6

Opera Diabolicus

1614

6

Opera IX

The Call Of The Wood

5

Opeth

Still Life	10
Ghost Reveries	10
Morningrise	9
My Arms, Your Hearse	9
Blackwater Park	9
Watershed	9
Orchid	8
Deliverance	7
Damnation	7
Heritage	7
Sorceress	3
Pale Communion	2
In Cauda Venenum	2

Ophidian I

Solvet Saeclum

5

Ophis

The Dismal Circle

6

Opus Arise

Revelation

6

Orbit Culture

Rasen

5

Orchid

The Mouths Of Madness

5

Orden Ogan

To The End	5
Easton Hope	4

Orecus

The Obliterationist

5

Orgone

The Joyless Parson

5

Origin

Entity

5

Orkrist

Reginae Mysterium

5

Orodruin

Ruins Of Eternity

5

Orphanage

By Time Alone

5

Orphaned Land

Mabool: The Story Of The Three Sons Of Seven	10
Kna'an [Collaboration]	9
El Norra Alila	8
Sahara	8
Ararat [EP]	8
The Never Ending Way Of ORwarriOR	8
All Is One	8
Unsung Prophets & Dead Messiahs	7

Orpheus Omega

Partum Vita Mortem	6
Bleed The Way	5
Resillusion	5

Osiah

Terror Firma

5

Ossian

Titkos Ünnep

5

Ostrogoth

Full Moon's Eyes [EP]	5
Ecstasy And Danger	5

Otep

Sevas Tra

5

Ou

One

4

Outer Heaven

Realms Of Eternal Decay

5

Overcharge

Speedsick

6

Overkill

Taking Over	10
The Years Of Decay	9
Ironbound	9
The Electric Age	8
Feel The Fire	7
Under The Influence	7
From The Underground And Below	7
Horrorscope	6
I Hear Black	5
Immortalis	5
The Grinding Wheel	5
The Wings Of War	5
Scorched	5
W.F.O.	4
Necroshine	4
White Devil Armory	4

Ovid's Withering

Scryers Of The Ibis

5

Oz

Fire In The Brain

4

Ozzy Osbourne

The Ultimate Sin	9
Speak Of The Devil [Live]	8
Blizzard Of Ozz	7
Diary Of A Madman	7
Bark At The Moon	5
No More Tears	5
No Rest For The Wicked	4

P.H.O.B.O.S.

Atonal Hypermnesia

5

Paara

Riitti

6

Pagan Altar

Lords Of Hypocrisy

5

Pagan Reign

Tverd (Ancient Fortress)

5

Pagan's Mind

Celestial Entrance	8
Enigmatic : Calling	8
Infinity Divine	6