The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Transliteration template errors (0 members)
- Trilogies (3 members)
- Twilight Theater Merchandise (0 members)
- Twilight Theater merchandise (3 members)
- Typing-aid templates (12 members)
- Ultraviolet Merchandise (0 members)
- Ultraviolet merchandise (12 members)
- Unicode character modules (1 member)
- Unknown parameters (0 members)
- Unwanted pages (859 members)
- User documentation pages (0 members)
- User namespace templates (1 member)
- Userboxes (1 member)
- Userboxes with insufficient color contrast (0 members)
- Utility templates (2 members)
- Verkkopaita merchandise (0 members)
- Video games (14 members)
- Webshop merchandise (17 members)
- Website images (1 member)
- WikiProject Albums templates (3 members)
- WikiProject Short descriptions (3 members)
- WikiProject Songs templates (3 members)
- Wiki images (115 members)
- Wikidata modules (2 members)
- Wikidata templates (2 members)
- Wikidata tracking categories (0 members)
- Wikipedia-specific image insertion templates (1 member)
- Wikipedia Lua-related templates (2 members)
- Wikipedia XHTML tag-replacing templates (12 members)
- Wikipedia archived wrapper templates (2 members)
- Wikipedia article titles (1 member)
- Wikipedia formatting templates (6 members)
- Wikipedia fully protected modules (1 member)
- Wikipedia fully protected templates (158 members)
- Wikipedia infoboxes (1 member)
- Wikipedia magic word templates (2 members)
- Wikipedia metatemplates (9 members)
- Wikipedia modules (1 member)
- Wikipedia multilingual support templates (1 member)
- Wikipedia page-name maintenance templates (1 member)
- Wikipedia page-section templates (3 members)
- Wikipedia pages with strange ((documentation)) usage (18 members)
- Wikipedia requested audio of songs (0 members)
- Wikipedia section templates (1 member)
- Wikipedia see also (1 member)
- Wikipedia templates which apply NOINDEX (1 member)
- Wikipedia utility modules (1 member)
- Wikitext processing templates (2 members)
- Wikitext typing-aid templates (8 members)
- Wristbands (12 members)