1. Obituary "Slowly We Rot" (1989) + "Cause Of Death" (1990) [2CD "Two From The Vault" re-release (2003)]
2. Obituary "Cause Of Death" (1990)
3. Obituary "The End Complete" (1992) + "World Demise" (1994) [2CD "Two From The Vault" re-release (2004)]
4. Obituary "Back From The Dead" (1997)
5. Obituary "Frozen In Time" (2005)
6. Obscura "Retribution" (2006)
7. Obsession "Martial Law" [EP] (1983)
8. Ocean, The "Anthropocentric" (2010)
9. Oceano "Depths" (2008) [includes DVD]
10. Oceano "Revelation" (2017)
11. Octinomos "Welcome To My Planet" (2000)
12. Odin "By The Gods" [compilation] (2001) [compiles "Caution" [single] (1983), "Don't Take No For An Answer" [EP] (1985) and "The Gods Must Be Crazy" [EP] (1990)]
13. Old Man's Child "Born of the Flickering (1995)
14. Old Man's Child "The Pagan Prosperity" (1997)
15. Old Man's Child "Ill-Natured Spiritual Invasion" (1998)
16. Old Man's Child "Revelation 666: The Curse of Damnation" (2000)
17. Old Man's Child "In Defiance Of Existence" (2003)
18. Old Man's Child "Vermin (2005)
19. Old Man's Child "Slaves of the World (2009)
20. Omen "Battle Cry" (1984)
21. Omen "Warning Of Danger" (1985)
22. Omen "The Curse" (1986) + "Nightmares" [EP] (1987) [1?CD re-release 1996]
23. Opeth "Still Life" (1999) [2008 re-release]
24. Omen "Eternal Black Dawn" (2003)
25. Omnium Gatherum "Grey Heavens" (2016)
26. One-T "The One-T ODC" (2002)
27. Onkel Tom Angelripper "Ein Straus bunter Melodien" (2006)
28. Onslaught "The Force" (1986)
29. Onslaught "In Search Of Sanity" (1989)
30. Onslaught "Sounds Of Violence" (2011)
31. Operation Mindcrime "The Key" (2015)
32. Opeth "Orchid" (1995)
33. Opeth "Morningrise" (1996)
34. Opeth "My Arms, Your Hearse" (1998)
35. Opeth "Blackwater Park" (2001)
36. Opeth "The Drapery Falls (Edit)" [single]
37. Opeth "Deliverance" (2002)
38. Opeth "Damnation" (2003)
39. Opeth "Ghost Reveries" (2005)
40. Opeth "Ghost Reveries" [Special Edition?] (2006?) [2-disc? CD & DVD??; includes "Soldier Of Fortune" Deep Purple cover?]
41. Opeth "Watershed" (2008)
42. Opeth "Heritage" (2011)
43. Opeth "Pale Communion" (2014)
44. Opeth "In Cauda Venenum" (2019) [2022 3CD Limited Edition]
45. Oppressor "Agony" (1996)
46. Oppressor "Elements Of Corrosion" (1998)
47. Orange 9mm "Driver Not Included" (1995)
48. Orange Goblin "Back From The Abyss" (2014)
49. Orff, Carl "Carmina Burana" [CDR?]
50. Origin "Origin" (2000) [note: problem with track #8 about 2:17 or so; looks like scratches, not pressing defect?]
51. Origin "Informis Infinitas Inhumanitas" (2002)
52. Origin "Echoes of Decimation" (2005)
53. Origin "Antithesis" (2008)
54. Origin "Unparalleled Universe" (2017)
55. Osbourne, Ozzy "Blizzard Of Ozz" (1980)
56. Osbourne, Ozzy "Diary Of A Madman" (1981)
57. Osbourne, Ozzy "Bark At The Moon" (1983)
58. Osbourne, Ozzy "The Ultimate Sin" (1986) [22 Bit SBM Digital Re-Master (Japan?)]
59. Osbourne, Ozzy "No Rest For The Wicked" (1988)
60. Osbourne, Ozzy "No More Tears" (1991)
61. Osbourne, Ozzy "Ozzmosis" (1995)
62. Osbourne, Ozzy "Down To Earth" (2001)
63. Osbourne, Ozzy "Under Cover" (2005)
64. Osbourne, Ozzy "Black Rain" (2007)
65. Osbourne, Ozzy "Scream" (2010)
66. Osbourne, Ozzy "Ordinary Man" (2020)
67. Osbourne, Ozzy "Patient Number 9" (2022)
68. Otep "Jihad" [EP] (2001)
69. Otep "Sevas Tra" (2002)
70. Otep "House Of Secrets" (2004)
71. Otep "The Ascension" (2007)
72. Otep "Smash The Control Machine" (2009)
73. Otep "Atavist" (2011)
74. Otep "Sounds Like Armageddon" (2012)
75. Otep "Hydra" (2013)
76. Otep "Generation Doom" (2016) [deluxe digipak with bonus tracks]
77. Otep "Kult 45" (2018)
78. Overdose "Circus Of Death" (1992)
79. Overdose "Progress Of Decadence" (1993)
80. Overdose "Scars" (1995)
81. Overkill "Feel The Fire" (1985)
82. Overkill "Taking Over" (1987)
83. Overkill "Under The Influence" (1988)
84. Overkill "The Years Of Decay" (1989)
85. Overkill "Horrorscope" (1991)
86. Overkill "I Hear Black" (1993)
87. Overkill "W.F.O." (1994)
88. Overkill "The Killing Kind" (1996)
89. Overkill "Fuck You ...And Then Some" [compilation] (1996) [contains "Overill" [EP] (1984), "Fuck You" [EP] (1987) and two live tracks]
90. Overkill "From The Underground And Below" (1997)
91. Overkill "Necroshine" (1999)
92. Overkill "Coverkill" (1999) [covers]
93. Overkill "Bloodletting" (2000)
94. Overkill "Killbox 13" (2003)
95. Overkill "Relixiv" (2005)
96. Overkill "Immortalis" (2007)
97. Overkill "Ironbound" (2010)
98. Overkill "The Electric Age" (2012)
99. Overkill "White Devil Armory" (2014)
100. Overkill "The Grinding Wheel" (2017)
101. Overkill "The Wings Of War" (2019)
102. Overkill "Scorched" (2023)
103. Oxiplegatz "Sidereal Journey" (1998)