The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Black left feminism (2 members)
- Black nationalism (9 members)
- Black nationalists (2 members)
- Black people murdered by US police (2 members)
- Blocked editors (14 members)
- Bolsheviks (8 members)
- Book covers (1 member)
- Book review websites (1 member)
- Books (14 members)
- Books not in our library (5 members)
- Books with missing cover (1 member)
- Bourgeois governments (1 member)
- Bourgeois media (16 members)
- Bourgeois revolutionaries (4 members)
- Bourgeois social media (1 member)
- Box-header with insufficient title contrast (4 members)
- Brazilian citizens (1 member)
- Brazilian communists (2 members)
- Brazilian journalists (1 member)
- BreadTube (5 members)
- Breadtube (0 members)
- British Prime Ministers (14 members)
- British anti-imperialists (1 member)
- British communist parties (7 members)
- British communists (4 members)
- British people of German descent (1 member)
- British political economists (3 members)
- British socialists (1 member)
- CIA-backed protests (2 members)
- CIA assets (5 members)
- CIA front groups (16 members)
- CIA operations (6 members)
- CIA plants (4 members)
- CPA comrades (0 members)
- CPB comrades (0 members)
- CPGB-ML comrades (0 members)
- CPI(M) comrades (0 members)
- 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)