From PPI
The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Budgets (2 members)
- Bulgaria (1 member)
- CC-BY (11 members)
- CC-BY-3.0 (40 members)
- CC-BY-SA-3.0 (10 members)
- CC license tags (7 members)
- Canada (1 member)
- Categories (38 members)
- Chile (1 member)
- Clipart (1 member)
- Communication (18 members)
- Communications (0 members)
- Conference (10 members)
- Conference 2011 (3 members)
- Conference 2012 (3 members)
- Conference 2013 (50 members)
- Conference 2014 (8 members)
- Conference 2015 (45 members)
- Conference 2016 (2 members)
- Conference 2018 (2 members)