| Map | Title | Author | Players | |
|---|---|---|---|---|
| DM-obsession | Obsession | Keith Miller | 2-8 | |
| DM-Obstinate | Obstinate![Tourney] | -=Laura=- | 1 on 1 ; 2 teams of 2 | |
| DM-Octarena | DM-Octarena | <aoi>Thor | 4 | |
| DM-ODB666=WareHouse= | DM-ODB666=WareHouse= | DEMON ACE =ODB666= | 2-12 | |
| DM-Odin | Odin's Quest | EZkeel | 2 - 8 | |
| DM-Odin's_Arena | Odin's Arena | RT Hay | 6-10 | |
| DM-Old-West | DM-Old-West | Unknown | 8 to 12 | |
| DM-OldRuins | DM-OldRuins | Diego | Unknown | |
| DM-Omega | Crazy bitch | {ROTA}Omega-{ROTA}Vegeta | 4-6 | |
| dm-omen | DM-OMEN \ [LOR]MAP | [LoR]Nasir-{DF}- | 4 | |
| DM-Opentrenchwar | Open Trenchwar | dirty~Bob | 3-8 | |
| Dm-OrganicArenas | Organic Arenas | :LoH:Lord McNeiL | 4-8 | |
| DM-Osiria | Osiria | Paul.C.Roberts | 4-8 | |
| DM-Ostara | Ostara | -=(GTC)=-$TV | 4 - 6 | |
| DM-oueyviroth | oueyviroth (i made that up) | -=[AVM]hellknight=- | >4 | |
| DM-Ouroboros | Ouroboros Training Facility | DarkToad & Testicules | 6-12 | |
| DM-Owwie Pit! | <(+H-H+)>Yo bone's gonna hurt! | <(+H-H+)>Warlord=== | 6 | |
| DM-Oxkron | DM-Oxkron | FµÑz£øÑ | Unknown |