The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Austrian military personnel (1 member)
- Austrian military personnel of the Austro-Slovene conflict in Carinthia (1 member)
- Austrian politicians (1 member)
- Austro-Hungarian military personnel of World War I (1 member)
- Austro-Hungarian military personnel of the First World War (1 member)
- Author: Vladimir Lenin (0 members)
- Autonomous regions in China (4 members)
- Ba'athist states (1 member)
- Balkanization maps (3 members)
- Banned editors (0 members)
- Bar charts (6 members)
- Bar graphs (0 members)
- 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)
- Bourgeois media (16 members)
- Bourgeois revolutionaries (5 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 political parties (3 members)
- British politicians (1 member)
- British socialists (1 member)