The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Overlords images (3 members)
- OxyPen images (1 member)
- Oya System (5 members)
- Oza images (2 members)
- P-52 Merlin images (33 members)
- P-72 Archimedes images (39 members)
- P4-AR images (11 members)
- P6-LR Sniper Rifle (1 member)
- P6-LR Sniper Rifle images (9 members)
- P8-AR images (3 members)
- P8-SC images (15 members)
- PAB-1 images (1 member)
- PAB-1 set (2 members)
- PAː Taser Pistol images (5 members)
- PTV images (18 members)
- P series (2 members)
- Pages needing citations (101 members)
- Pages needing cleanup (93 members)
- Pages queued for review (5 members)
- Pages using DynamicPageList3 parser function (3,058 members)
- Pages using DynamicPageList3 parser tag (4 members)
- Pages using DynamicPageList parser function (0 members)
- Pages using DynamicPageList parser tag (0 members)
- Pages using Tabber parser tag (390 members)
- Pages using deprecated source tags (2 members)
- Pages using duplicate arguments in template calls (24 members)
- Pages where expansion depth is exceeded (1,976 members)
- Pages where template include size is exceeded (2 members)
- Pages with TemplateStyles errors (5 members)
- Pages with broken file links (275 members)
- Pages with broken graphs (0 members)
- Pages with graphs (2 members)
- Pages with ignored display titles (4 members)
- Pages with non-numeric formatnum arguments (572 members)
- Pages with outdated information (19 members)
- Pages with reference errors (26 members)
- Pages with script errors (27 members)
- Pages with short description (3,984 members)
- Pages with syntax highlighting errors (11 members)
- Pages with translations (0 members)
- Pages with unconfirmed content (1 member)
- Paladin set (1 member)
- Pants (33 members)
- Pants images (1 member)
- ParaMed Medical Device images (9 members)
- Parallax Rifle images (2 members)
- Parasite Replica Helmet images (1 member)
- Parasite V: Dark Birth Replica Helmet images (1 member)
- Partner Icons (1 member)
- Party chairs (2 members)