The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Basic Marxism–Leninism study plan by r/communism (20 members)
- Belarus (1 member)
- Belt and Road Initiative (2 members)
- 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)