- Obscuritas Est Imperium (Black Metal-Germany)
- Obscurium (Dark Ambient-Brazil)
- Obscureism (Black Metal-USA)
- Obscurum Malum (Black Metal-Italy)
- Oscuriam (Symphonic Metal-Mexico)
- Oculus Infernum (Black Metal-Italy)
- Obscuredream (Melodic Black-China)
- Obscenium (Technical Death-Australia)
- Oscurus Infernal (Black Metal-Ecuador)
- Ossuarium (Death Metal-USA)