The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Hungarian communists (1 member)
- I Ain't Marching Anymore (4 members)
- Idealism (12 members)
- Ideological conflicts (1 member)
- Ideological infrastructure (26 members)
- Ideology of the Communist Party of China (6 members)
- Ideology of the Communist Party of the Soviet Union (1 member)
- Ideology of the Democratic People's Republic of Korea (1 member)
- If I Had a Hammer: Songs of Hope and Struggle (1 member)
- Illegal states (5 members)
- Images (13 members)
- Imperial Russian Army personnel (1 member)
- Imperialism (19 members)
- Imperialist companies (18 members)
- Imperialist countries (27 members)
- Imperialist intergovernmental organizations (9 members)
- Imperialist organizations (21 members)
- Imperialist political parties (13 members)
- Imperialist propaganda (28 members)
- Imperialist secret police (11 members)
- Imperialist think tanks (3 members)
- Imperialist treaties (1 member)
- Imperialist wars (1 member)
- Imperialists (19 members)
- Incomplete (0 members)
- Incomplete library works (10 members)
- Indian Marxists (7 members)
- Indian revolutionaries (1 member)
- Indigenous People of the Americas (2 members)
- Indigenous leaders (2 members)
- Industrial Workers of the World (1 member)
- Industrial policies (1 member)
- Infoboxes without native name language parameter (9 members)
- Informational essays (2 members)
- Infrastructure projects (1 member)
- Instruments of the bourgeoisie (3 members)
- Insurgencies (1 member)
- Intelligence Operations (9 members)
- Intelligence agencies (2 members)
- Intelligence operations (1 member)
- Intergovernmental organizations (15 members)
- International Auxiliary Languages (0 members)
- International Communist Organisations (0 members)
- International auxiliary languages (2 members)
- International communist organizations (10 members)
- International socialist organizations (1 member)
- Interviews (10 members)
- Iran (2 members)
- Iran memes (1 member)
- Iranian state media (1 member)