The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Ultra Violet Maps (30 members)
- Ultra Violet Nexus Worlds (8 members)
- Uneven Dream (8 members)
- Uneven Dream Authors (20 members)
- Uneven Dream BGM (4 members)
- Uneven Dream Characters (4 members)
- Uneven Dream Collectables (4 members)
- Uneven Dream Guides (11 members)
- Uneven Dream Locations (142 members)
- Uneven Dream Nexus Worlds (17 members)
- Uneven Dream Removed Content (9 members)
- Uneven Dream Screenshots (3 members)
- Unused (75 members)
- Uroyu (1 member)
- Uwa (12 members)
- Uwonozoki (16 members)
- VANEGI (8 members)
- Victikirby (1 member)
- Videos (120 members)
- Vivi (3 members)
- VoxlAlien (3 members)
- WXeoWvpbbM (6 members)
- Walk Cycles (62 members)
- Wataru (183 members)
- Widdershins (2 members)
- Widgets (1 member)
- Wiki-dependent (8 members)
- Wiki icons (1 member)
- Wikis (21 members)
- Wooglee (2 members)
- World Map Galleries (18 members)
- Xen (1 member)
- YNOproject (6 members)
- YNOproject Badges (21 members)
- Yama (1 member)
- Yarshmellow (10 members)
- Yasakoten (7 members)
- Yawaraka (10 members)
- Yeris (51 members)
- Yuki-Hitsuji (5 members)
- YumeWiki (8 members)
- Yume 2kki (13 members)
- Yume 2kki Annotated Maps (9 members)
- Yume 2kki Authors (113 members)
- Yume 2kki BGM (540 members)
- Yume 2kki Characters (49 members)
- Yume 2kki Collectables (24 members)
- Yume 2kki Connecting Maps (40 members)
- Yume 2kki Contributors (4 members)
- Yume 2kki Effect NPCs (22 members)