The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Freopedia (1 member)
- Furnishings (1 member)
- Furniture (2 members)
- Future (2 members)
- Future plans (1 member)
- GIS (1 member)
- GITenberg (3 members)
- GLAM (1 member)
- GNU (1 member)
- GPS (1 member)
- Gadgets (2 members)
- Gallery (1 member)
- Gallery3 (1 member)
- Gallery Project (1 member)
- Games (1 member)
- Gardening (8 members)
- Gardens (1 member)
- Gaston Bachelard (1 member)
- Gears (1 member)
- Genealogy (7 members)
- General International Standard Archival Description (1 member)
- Geogeeks (1 member)
- Geometry (1 member)
- George Eliot (1 member)
- George Gissing (1 member)
- George Steiner (1 member)
- Ghost (1 member)
- Git (3 members)
- Github (3 members)
- GluePHP (1 member)
- Glueless (1 member)
- Gmail (1 member)
- God (1 member)
- Grammar (1 member)
- Grand Lane (1 member)
- GraphViz (1 member)
- Graphics (3 members)
- Gratis (1 member)
- Gravatars (1 member)
- Greens (1 member)
- Greg Maxwell (1 member)
- Grinders (1 member)
- Guerilla preservation (2 members)
- H. Margaret Wilson (1 member)
- HTML (2 members)
- HTTP (1 member)
- Hacking (2 members)
- Hamilton Hill (3 members)
- Hamilton Road (1 member)
- Hand planes (1 member)