The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- CPUSA (4 members)
- CPUSA comrades (0 members)
- CPUSA members (11 members)
- Campaigns (1 member)
- Canada (2 members)
- Canada (essays) (1 member)
- Canadian anti-communists (3 members)
- Canadian communists (5 members)
- Canadian neo-Nazis (1 member)
- Canadian politicians (1 member)
- Canadian white supremacists (1 member)
- Canadians by descent (2 members)
- Canadians of Scottish descent (1 member)
- Canadians of Ukrainian descent (1 member)
- Capital volume I concepts (14 members)
- Capitalism (26 members)
- Capitalist political parties (5 members)
- Capitalist progaganda (20 members)
- Capitalist propaganda (3 members)
- Capitalist terminology (17 members)