The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Reading (4 members)
- Reading (FAQ) (8 members)
- Recipes (8 members)
- Reddit (68 members)
- Redirect templates (1 member)
- Renaissance (1 member)
- Research (2 members)
- Research (FAQ) (12 members)
- Resizing templates (5 members)
- Rhetoric (FAQ) (21 members)
- Riding (63 members)
- Ridley Scott (1 member)
- Robert Browning (2 members)
- Robert Fripp (2 members)
- Robert Frost (1 member)
- Robert Heinlein (0 members)
- Robert Lowell (1 member)
- Robert Zemeckis (3 members)
- Roman (2 members)
- Romanticism (1 member)
- Rush (17 members)
- Rómulo Gallegos (1 member)
- Salman Rushdie (4 members)
- Samuel Beckett (3 members)
- Samuel Taylor Coleridge (2 members)
- Science (7 members)
- Science Fiction (170 members)
- Scrambler (30 members)
- Self-published work (145 members)
- Semantic markup templates (2 members)
- Service (1 member)
- Sheri S. Tepper (2 members)
- Short Fiction (10 members)
- Shortcut templates (1 member)
- Shot with Canon (84 members)
- Shot with Fujifilm (25 members)
- Shot with Leica (1 member)
- Shot with Sony (55 members)
- Sidebar templates (1 member)
- Skopar 3.5/21 (0 members)
- Soapbox (9 members)
- Software templates (1 member)
- Sony 1.8/55 (5 members)
- Sophocles (10 members)
- Spring 1998 (0 members)
- Spring 1999 (0 members)
- Spring 2002 (1 member)
- Spring 2013 (4 members)
- Spring 2017 (8 members)
- Spring 2018 (1 member)