25 wads
| File | Name | Author | Iwad | Demos | Length |
|---|---|---|---|---|---|
| orca | Orca | Jizzwardo | doom2 | 2 | 7:14 |
| ore15 | ore15 | Steve Johnson | doom2 | 2 | 0:26 |
| orifice | World Orifice | Benjogami | doom2 | 2 | 4:40:31 |
| origwad | origwad | Jeff Bird | doom | 50 | 30:26 |
| orin01 | orin01 | Orin Flaharty | doom2 | 3 | 4:04 |
| orpheus | orpheus | Shane | doom | 22 | 27:29 |
| oscl | oscl | Forli | doom2 | 2 | 18:53 |
| os-doa | os-doa | Philip Renshaw | doom2 | 2 | 38:54 |
| osiris | osiris | Glen Payne & Marshal Bostwick | doom2 | 6 | 27:37 |
| oskyrt | oskyrt | Hardcore_Gamer | doom | 2 | 14:40 |
| oskyrt2 | Beyond Horrible! | Hardcore_gamer | doom | 1 | 0:27 |
| osp | osp | Karthik Abhirama | doom | 2 | 12:09 |
| otakondm | otakondm | Mark Sachs | doom2 | 2 | 0:25 |
| ottawa09 | ottawa09 | Jean-Serge Gagnon | doom | 1 | 36:59 |
| outback | outback | Adam Windsor | doom2 | 1 | 2:21 |
| outpost2 | outpost2 | Radromity | doom2 | 6 | 3:29 |
| outposta | Outpost Alpha | odysseyofnoises | doom2 | 1 | 2:25 |
| outposta_2018 | Outpost Alpha | odysseyofnoises | doom2 | 2 | 4:22 |
| outposth | outposth | Rubber Duck | doom2 | 1 | 1:58 |
| overboard | Overboard | mouldy | doom2 | 222 | 11:37:57 |
| overflow | Overflow | Chris Kendell (Somniac) | doom2 | 2 | 3:34 |
| overload | Overload Deathmatches | Ola Bjorling | doom2 | 51 | 2:46 |
| oversat | Oversaturation | NoReason | doom2 | 5 | 1:09:48 |
| oxbow | oxbow | Tim Williams | doom2 | 1 | 4:04 |
| ozonia | Ozonia | Deadwing | doom2 | 112 | 3:33:37 |