Obsidian Kingdom - A Year with no Summer
n, 2016, Season of Mist FRA
Obtest - Amžina Aušra
n, 2011, Ledo Takas LIT
Obtest - Auka Seniems Dievams
n, 2001, Leda Takas LIT (2011)
October Tide - In Splender Below
n, 2019, Agonia PL
Old Mans Child - Slaves of the World
n, 2009, Floga GRE (2018)
Olde - The Gates of Dawn
n, 2013, Soulseller NL
Omega Infinity - Solar Spectre
n, 2020, Seasons of Mist FRA
Omen - Battle Cry
ss, 1984, High Roller D (2022)
Omen - Into the Arena
n, 2012, No Remorse GRE
Oniricous - Ritos Diabolicos
n, 2013, Equinox SPA (2015)
Onslaught - The Force
ss, 1986, High Roller D (2019)
Opprobrium (Incubus) - Serpent Temptation
ss, 1988, High Roller D (2023)
Opus Forgotten - Demon of Destruction
m, 2000, Aftermath Music, NOR
Orcrist - Fallen
n, 2011, Aphelion UK
Orden Ogan - Final Days
ss, 2020, AFM D - clear vinyl
Ordo Inferus - Invictus et Aeternus
n, 2014, Doomentia CZ
Organismos - Manejos Invisibles
n, 2011, Me Saco un Ojo Records UK
Origin of Infinity - The Last Day on Earth
n, 2020, Origin of Infinity