The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Sighting Reports (0 members)
- Skeptical Advocates (9 members)
- Skeptical Organisations (2 members)
- Sleep (1 member)
- Somerset (0 members)
- South Yorkshire (4 members)
- Stage Shows (1 member)
- Stockport (1 member)
- Subject Indexes (4 members)
- Supernatural Fiction (2 members)
- Supernatural fiction (1 member)
- Surrey (1 member)
- Switzerland (0 members)
- TV Personalities (11 members)
- Tarot and Divination (0 members)
- Telepathy (0 members)
- Television (15 members)
- Templates (4 members)
- The Conjuring Universe (2 members)
- The Vault (27 members)
- The Vault Guidelines (18 members)
- The Vault Maintenance (0 members)
- The Vault Profiles (1 member)
- UFO/UAP (6 members)
- UFO Hotspots (2 members)
- UFO Locations (1 member)
- UFO Photographs and Videos (1 member)
- UFO tourism (1 member)
- UFOs and Sightings (0 members)
- Unexplained Phenomena (1 member)
- United Kingdom (1 member)
- United States of America (10 members)
- Urban Legend Reports (1 member)
- Urban Legends (1 member)
- Vault Administration (1 member)
- Vault Guidelines (1 member)
- Vault License Templates (6 members)
- Vault Maintenance (2 members)
- Vault Policies (2 members)
- Vault Templates (52 members)
- Vault chronology categories (2 members)
- Vault maintenance categories (1 member)
- Vermont (1 member)
- Waterloo, Ontario (1 member)
- West Yorkshire (1 member)
- Westminster (1 member)
- Witnesses (3 members)
- Writing Guidelines (1 member)
- Yvette Fielding (1 member)
- ✓ (82 members)