The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Puzzle video games (1 member)
- Religious belief and doctrine (1 member)
- Roblox (1 member)
- Rotational symmetry by order (2 members)
- SI base quantities (1 member)
- SVG created with ... templates (1 member)
- SVG historical pirate flags (1 member)
- SVG icons by theme (2 members)
- Scalar physical quantities (1 member)
- Seashells (1 member)
- Sega Dreamcast (0 members)
- Sega Technical Institute games (1 member)
- Sega consoles (2 members)
- Self-published work (1 member)
- Semantic units (1 member)
- Sets (groups) (1 member)
- Shapes (1 member)
- Shiba Inu (1 member)
- Single-player video games (1 member)
- Sixth-generation video game consoles (2 members)
- Snow crystals (1 member)
- Snowflakes (0 members)
- Software (1 member)
- Software by name (1 member)
- Software icons by name (1 member)
- Sonic X-treme (0 members)
- Sonic the Hedgehog video games (1 member)
- Spacetime (1 member)
- Spiralia (1 member)
- Spiritism (1 member)
- Spirits (1 member)
- Spiritualism (1 member)
- String manipulation templates (1 member)
- Subtemplates (6 members)
- Supernatural legends (1 member)
- Tango project (0 members)
- Tango project/emblems (1 member)
- Taxon categories (13 members)
- Taxonomy (1 member)
- Technology (1 member)
- TemplateData documentation (1 member)
- Template Unknown (artist) (1 member)
- Template Unknown (author) (1 member)
- Template documentation (4 members)
- Template namespace templates (4 members)
- Template redirects (1 member)
- Templates:Unknown (1 member)
- Templates not requiring internationalization (4 members)
- Templates to include in Taxonavigation (1 member)
- Templates using LangSwitch for internationalisation (1 member)