| Year: | Title: | Label: | Medium: | Tracks: |
| OBITUARY - US - D |
| 1989 | Slowly We Rot | Roadracer | lp | 12 |
| 1990 | Cause of Death | Roadracer | cd | 09 |
| 1992 | The End Complete | Roadracer | cd | 09 |
| 1994 | World Demise | Roadrunner | cd | 12 |
| 1997 | Back from the Dead | Roadrunner | adv. mc | 12 |
| 1997 | Back from the Dead | Roadrunner | cd | 12 |
| 1998 | Dead | Roadrunner | cd | 16 |
| 2005 | Frozen In Time | Roadrunner | cd | 10 |
| 2007 | Xecutioner's Return | Candlelight | cd | 12 |
| 2008 | Left to Die | Candlelight | cd | 05 |
| 2009 | Darkest Day | Candlelight | cd | 13 |
| 2014 | Inked in Blood | Relapse | cd | 14 |
| 2023 | Dying of Everything | Relapse | cd | 10 |
| |
| OFFSPRING, THE - US - GR/PU |
| 1992 | Ignition | Epitaph | cd | 12 |
| 1994 | Smash | Epitaph | cd | 14 |
| 1994 | Self Esteem | Epitaph | cd | 03 |
| 1997 | Ixnay on the Hombre | Epitaph | cd | 14 |
| 1997 | Gone Away | Epitaph | cd | 04 |
| 1998 | Pretty Fly (For a White Guy) | Epitaph | cd | 02 |
| 1998 | Americana | Sony | m11 | 13 |
| 2000 | Conspiracy of One | Sony | m23 | 15 |
| 2003 | Splinter | Sony | m36 | 12 |
| |
| :OF THE WAND & THE MOON: - DK - AmbientDO/GO |
| 2001 | :emptiness:emptiness:emptiness: (promo) | Euphonious | cd | 09 |
| |
| O.L.D # - UK - GC/TECH |
| 1989 | Old Lady Drivers | Earache | m30 | 15 |
| 1995 | Formula | Earache | cd | 07 |
| |
| OLDFIELD, MIKE - UK - P/R |
| 1973 | Tubular Bells | Virgin | lp | 01 |
| 1974 | Hergest Ridge | Virgin | cd | 01 |
| 1975 | Ommadawn | Virgin | cd | 02 |
| 1975 | The Orchestral Tubular Bells | Virgin | cd | 02 |
| 1978 | Incantations | Virgin | cd | 04 |
| 1979 | Platinum | Virgin | lp | 05 |
| 1980 | QE2 | Virgin | lp | 09 |
| 1981 | The Consequences of Indecision | Happy Bird | lp | 05 |
| 1982 | Family Man | Virgin | single | 02 |
| 1983 | Five Miles Out | Virgin | cd | 05 |
| 1983 | Crisis | Virgin | cd | 06 |
| 1983 | Moonlight Shadow | Virgin | single | 02 |
| 1984 | Discovery | Virgin | lp | 08 |
| 1984 | The Killing Fields - soundtrack | Virgin | cd | 17 |
| 1987 | Islands | Virgin | cd | 07 |
| 1989 | Earth Moving | Virgin | cd | 09 |
| 1990 | Amarok | Virgin | lp | 01 |
| 1991 | Heavenīs Open | Virgin | cd | 06 |
| 1992 | Tubular Bells II | Virgin | lp | 14 |
| 1992 | Tattoo | Virgin | cd | 03 |
| 1993 | Elements - The best of Mike Oldfield | Virgin | cd | 16 |
| 1994 | The Songs of Distant Earth | Warner | cd | 17 |
| 1996 | Voyager | Warner | cd | 10 |
| 1998 | Tubular Bells III | Warner | cd | 11 |
| 1999 | Guitars | Warner | cd | 10 |
| 1999 | The Millennium Bell | Warner | cd | 11 |
| 2002 | Treslunas | Warner | dcd | 14 |
| 2008 | Music of the Spheres | Universal | cd | 14 |
| |
| OLDFIELD GROUP, THE MIKE - UK - P |
| 1982 | Mistake | Virgin | single | 02 |
| |
| OLD MAN'S CHILD - N - D/BM |
| 2000 | Revelation666 (promo) | Century Media | cd | 08 |
| |
| OMEN # - US - HM |
| 1984 | Battle Cry | Roadrunner | m33 | 10 |
| |
| ONE-WAY WARRIOR - F - T |
| 2008 | One-Way Warrior (promo) | Metal Blade | cd | 10 |
| |
| ONSLAUGHT - UK - T |
| 1985 | Power from Hell | MFN | m29 | 12 |
| 1986 | The Force | MFN | m29 | 07 |
| 1987 | Let there be Rock | London | m06 | 04 |
| 1988 | Shellshock | London | 112 | 03 |
| 1989 | In Search of Sanity | London | lp | 08 |
| 1989 | In Search of Sanity (2008 re-issue) | Candlelight Records | cd | 08 |
| 1989 | Welcome to Dying | London | m26 | 03 |
| |
| OPETH - S - BM/? |
| 2001 | Blackwater Park | MFN | cd | 08 |
| |
| ORDO INFERUS - S - D |
| 2014 | Invictus et Aeternus (promo) | Doomentia | cd | 12 |
| |
| ORGANIZATION, THE - US - HM/F |
| 1993 | The Organization | Unsafe Records | cd | 14 |
| |
| ORPHANAGE - NL - HM/D |
| 2004 | Driven | Nuclear Blast | cd | 14 |
| |
| ORPHANED LAND - IS - HM/D/Prog |
| 1994 | Sahara (2016 remaster) | Century Media | cd | 08 |
| 1996 | El Norra Alila (2016 remaster) | Century Media | cd | 13 |
| 2010 | The Never Ending Way of Warrior | Century Media | 2cd | 20 |
| 2014 | The Story of the Three Sons of Seven | Century Media | cd | 12 |
| 2016 | Orphaned Land & Amaseffer: Kna'an | Century Media | cd | 13 |
| 2018 | Unsing Prophets & Dead Messiahs | Century Media | cd | 13 |
| |
| ORTEGA - NL - SludgeDO |
| 2012 | 1634 | Aesthetic Death | cd | 07 |
| |
| OSBOURNE, OZZY - UK - HM |
| 1980 | Blizzard of Ozz | Jet Records | lp | 09 |
| 1980 | Blizzard of Ozz (re-issue) | Epic | cd | 10 |
| 1981 | Diary of a Madman | Jet Records | lp | 08 |
| 1981 | Diary of a Madman (re-issue) | Epic | cd | 09 |
| 1982 | Speak of the Devil | Jet Records | dlp | 12 |
| 1982 | Speak of the Devil (1995 rerelease) | Epic | cd | 12 |
| 1983 | Bark at the Moon | CBS | cd | 10 |
| 1984 | So Tired | CBS | ep | 05 |
| 1986 | The Ultimate Sin | CBS | cd | 09 |
| 1987 | Randy Rhoads Tribute | Epic | cd | 14 |
| 1988 | No Rest for the Wicked | CBS | cd | 11 |
| 1990 | Just say Ozzy | CBS | cd | 06 |
| 1991 | No More Tears | Epic | cd | 11 |
| 1991 | Mama I'm coming Home | Epic | cd | 03 |
| 1993 | Live & Loud | Epic | dlp | 21 |
| 1993 | Changes | Epic | cd | 04 |
| 1995 | Perry Mason | Epic | cd | 03 |
| 1995 | The Ballads of Ozz (promo) | Epic | cd | 04 |
| 1995 | I Just Want You (promo) | Epic | cd | 01 |
| 1996 | Ozzmosis | Epic | cd | 12 |
| 1996 | I Just Want You | Epic | cd | 03 |
| 1997 | The Ozzman Cometh | Epic | dcd | 18 |
| 2001 | Down to Earth | Epic | cd | 11 |
| 2001 | Gets Me Through | Epic | cd | 03 |
| 2002 | Dreamer | Epic | cd | 04 |
| 2002 | Live at Budokan | Epic | cd | 13 |
| 2002 | Live at Budokan | Epic | dvd | 14 |
| 2005 | Under Cover | Epic | cd | 14 |
| 2007 | Black Rain | Epic | cd | 10 |
| |
| OVERKILL - US - POW/T |
| 1985 | Feel the Fire | Noise | cd | 10 |
| 1987 | Taking Over | Megaforce | cd | 09 |
| 1987 | !!!Fuck You!!! | Megaforce | mini | 05 |
| 1988 | Under the Influence | Megaforce | cd | 09 |
| 1989 | The Years of Decay | Megaforce | cd | 09 |
| 1990 | Lifetime to Kill - Dusseldorf | bootleg | m23 | 11 |
| 1991 | Horrorscope | Megaforce | cd | 11 |
| 1993 | I Hear Black | Atlantic | cd | 11 |
| 1994 | W.F.O. | Atlantic | cd | 12 |
| 1995 | Wrecking your Neck - Live | CMC Rec. | dcd | 22 |
| 1996 | The Killing Kind | Concrete | cd | 10 |
| 1997 | From the Underground and Below (promo) | Steamhammer | cd | 10 |
| 1997 | From the Underground and Below | Steamhammer | cd | 10 |
| 1999 | Necroshine | Steamhammer | cd | 10 |
| 1999 | Coverkill (promo) | Steamhammer | cd | 12 |
| 2000 | Bloodletting | Steamhammer | cd | 10 |
| 2002 | Wrecking Everything - Live | Spitfire | cd | 13 |
| 2003 | Killbox 13 | Spitfire | cd | 10 |
| 2005 | RelixIV | Regain | cd | 10 |
| 2007 | Immortalis + dvd | BodigMusic | cd | 10 |
| 2010 | Ironbound | Nuclear Blast | cd | 10 |
| 2012 | The Electric Age | Nuclear Blast | cd | 10 |
| 2014 | White Devil Armory | Nuclear Blast | cd | 13 |
| 2017 | The Grinding Wheel | Nuclear Blast | cd | 10 |
| 2019 | The Wings of War | Nuclear Blast | cd | 10 |
| 2023 | Scorched | Nuclear Blast | cd | 10 |
| |
| OVERLORDS, THE # - DK - TECH |
| 1994 | All the Naked People | Arista | cd | 10 |
