The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Big tech (6 members)
- Bigotry (5 members)
- Billionaires (6 members)
- Biologists (7 members)
- Black Panther Party (6 members)
- 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)
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- CPGB-ML comrades (0 members)
- CPI(M) comrades (0 members)
- CPUSA (4 members)
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- 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)
- Capitalists (8 members)
- Censorship (4 members)
- Censorship by country (1 member)
- Censorship in the United States (4 members)
- Central American countries (7 members)
- Central Intelligence Agency (8 members)
- Charts (4 members)
- Child pornography defenders (2 members)
- China (1 member)
- Chinese Civil War (2 members)
- Chinese Companies (2 members)
- Chinese Soviet Republic (2 members)
- Chinese communists (7 members)
- Chinese dialects (2 members)
- Chinese leaders (5 members)
- Chinese politicians (5 members)
- Chinese propaganda posters (15 members)
- Chinese revolutionaries (1 member)
- Chinese state media (2 members)
- Christianity (7 members)
- Cities (22 members)
- City-states (1 member)
- Civil rights (2 members)
- Civil wars (6 members)
- Class society (5 members)
- Class warfare memes (1 member)
- Classical economists (3 members)
- Climate change (1 member)
- Closed source software (1 member)
- Coats of arms (1 member)
- Cold War (5 members)
- Colonial outposts (9 members)
- Colonialism (7 members)
- Colour Revolutions (5 members)
- Comintern (1 member)
- Commonwealth of Nations templates (1 member)
- Communes (1 member)
- Communism (11 members)