The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- 3D printer (1 member)
- 3D printing (1,246 members)
- 3d bioprinting (1 member)
- 3d printing (206 members)
- 4777 TRIZ 3D printers (41 members)
- 5490-16 (32 members)
- 5490-19 (33 members)
- 5490-2017 (20 members)
- 5490-2020 (16 members)
- 5490-2021 (15 members)
- 5621 Users 2020 (25 members)
- 5970-2017 (0 members)
- 777-2014 People (2 members)
- 777-2015 People (1 member)
- 777 Users 2019 (96 members)
- AGlover (1 member)
- AI (18 members)
- ALLFED (1 member)
- ALL SAFE (71 members)
- ANTH329 Media and International Social Change (55 members)