The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Oudn (102 members)
- Ouri (26 members)
- OutlanderS3S (2 members)
- Oversomnia (6 members)
- Oversomnia Characters (1 member)
- Oversomnia Guides (5 members)
- Oversomnia Locations (60 members)
- Oversomnia Nexus Worlds (0 members)
- PGray (9 members)
- Pages using DynamicPageList3 parser function (188 members)
- Pages using HTML (22 members)
- Pages with broken file links (235 members)
- Pages with ignored display titles (4 members)
- Pages with script errors (16 members)
- Pages with too many expensive parser function calls (0 members)
- Parallax Background (9 members)
- Pinu (21 members)
- Playable Characters (20 members)
- Preload (4 members)
- Property setting templates (3 members)
- Proton (5 members)
- QMark (16 members)
- Quote templates (2 members)
- Qxy (242 members)
- RM824 Somnium (3 members)
- ROKU95 (109 members)
- Raptarr8 (1 member)
- Reading help (1 member)
- Removed Content (122 members)
- River (7 members)
- Rollaby (4 members)
- Roninnozlo (5 members)
- Roverkibb (3 members)
- Ruri (24 members)
- Rurima (15 members)
- Río (129 members)
- SMW output templates (2 members)
- Sabamiso (11 members)
- Sakiyuki's Worlds (11 members)
- Screenshots (274 members)
- Shakzass (2 members)
- She Awaits (5 members)
- She Awaits Characters (2 members)
- She Awaits Guides (5 members)
- She Awaits In Development (1 member)
- She Awaits Locations (23 members)
- She Awaits Nexus Worlds (5 members)
- Shigurin (89 members)
- Sniperbob (54 members)
- Someday (6 members)