The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- (DT)Ecology (14 members)
- (DT)Energy (10 members)
- (DT)Governance (2 members)
- (DT)Management (2 members)
- (DT)Shipping (6 members)
- (NS)Currents (1 member)
- (NS)Ecology (28 members)