The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Animal (1 member)
- Plotting (0 members)
- Train (2 members)
- Api (0 members)
- Milliampere (0 members)
- StudyReport (0 members)
- Model (6 members)
- SquareAngstrom (0 members)
- EuEmissionSectorDivision (0 members)
- Prüfkörper (0 members)
- TemperatureChangeDevice (0 members)
- Ampere (0 members)
- City (0 members)
- SensibleSolidHeatStorageObject (0 members)
- EnzymeUnit (0 members)
- Propulsion (1 member)
- CodeSource (0 members)
- HardCoal (2 members)
- Port (2 members)
- FuelTransport (1 member)
- RunOfRiverPowerPlant (0 members)
- ModellingSoftware (0 members)
- Agent (14 members)
- ObjectiveFunction (0 members)
- Ratio (0 members)
- Recipe (4 members)
- Centimorgan (0 members)
- Ramping (1 member)
- Electrical (0 members)
- TertiaryControl (0 members)
- AccreditationDocument (0 members)
- ExclusionSubsetOntologyModule (0 members)
- LatentFluidGaseousHeatStorageObject (0 members)
- MilliliterPerKilogram (0 members)
- EndTime (0 members)
- FuelDemand (0 members)
- MillimetersPerDay (0 members)
- Canal (0 members)
- HubHeight (0 members)
- EnvironmentalTemperature (0 members)
- Diameter (5 members)
- BiogenicIndustrialWasteFuel (0 members)
- MicromolePerKilogram (0 members)
- MicromolePerLitre (0 members)
- RenewableEnergyShare (0 members)
- Second (0 members)
- PlaqueFormingUnitPerVolume (1 member)
- LuminousIntensityUnit (1 member)
- HeatingGridComponent (0 members)
- EmissionConstraint (0 members)