The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Diagrams (1 member)
- Dichotomy (11 members)
- Dictionaries (1 member)
- Digitisation (2 members)
- Digitization (1 member)
- Dispair (2 members)
- Display Title (2 members)
- DjVu (2 members)
- Docker (1 member)
- Documentation (2 members)
- Dogs (2 members)
- Doing it the WRONG way (1 member)
- DokuWiki (6 members)
- Donating (2 members)
- Door jamb (2 members)
- Doubt (2 members)
- Douglas Adams (1 member)
- Dovetails (4 members)
- Dovevtails (2 members)
- Dries Buytaert (1 member)
- Drupal (11 members)
- Drush (1 member)
- Duplication of content (1 member)
- ERD (1 member)
- Ebooks (7 members)
- Editing (3 members)
- Eggs (2 members)
- Elasticsearch (1 member)
- Elections (1 member)
- Elegance (1 member)
- Email (7 members)
- Emma (1 member)
- Emotion (2 members)
- Employment (1 member)
- Entities (1 member)
- Entity Relationship Diagrams (1 member)
- Environments (1 member)
- Ephemera (1 member)
- Epub (2 members)
- Equipment (1 member)
- Ereaders (3 members)
- Errors (1 member)
- Escape (1 member)
- Events (3 members)
- Excel (2 members)
- Exhibitions (1 member)
- Exiftool (1 member)
- Exploration (4 members)
- Exploring (47 members)
- Exporting (2 members)