The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Regions of the UK (4 members)
- Relation of production (1 member)
- Religion (7 members)
- Religions (5 members)
- Republic of Korea (1 member)
- Republics of the Soviet Union (8 members)
- Restaurant chains (1 member)
- Retired comrades (3 members)
- Revisionism (14 members)
- Revisionists (14 members)
- Revolution (1 member)
- Revolutionaries (26 members)
- Revolutionaries by nationality (4 members)
- Revolutionary Base Area (1 member)
- Revolutionary tactics (1 member)
- Revolutions (9 members)
- Right-wing ideologies (22 members)
- Right wing political parties (4 members)
- Rockefeller family (1 member)
- Rodney family of Delaware (1 member)