The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- SolarThermalPowerUnit (0 members)
- WaterElectrolyser (0 members)
- EngineeredMaterial (3 members)
- TensileTestNode (1 member)
- DataAboutAnOntologyPart (4 members)
- PrimaryEnergyConsumptionCalculationMethod (3 members)
- Femtomolar (0 members)
- DecommissioningTime (0 members)
- Import (1 member)
- PassengerKilometre (0 members)
- LengthValue (0 members)
- BusStation (0 members)
- OceanCurrent (0 members)
- ChangeOfTransverseDimension (0 members)
- DirectEquivalentMethod (0 members)
- Date (0 members)
- UnitPrefix (2 members)
- ProgrammingLanguage (0 members)
- Area (2 members)
- TonPerHectare (0 members)
- DensityUnit (3 members)
- OSW9a49d8d78eed51a4971817c0d4f459b2 (1 member)
- ProcessSustainability (0 members)
- Millimeter (0 members)
- Micromolal (0 members)
- MemoItem (0 members)
- SulphurHexafluoride (0 members)
- CalibrationRange (0 members)
- IndustrialWasteThermalEnergy (0 members)
- NodeSeries (0 members)
- ElectricHeatPump (0 members)
- CrudeOil (2 members)
- WastePowerPlant (0 members)
- ActivityOfARadionuclideUnit (7 members)
- MicrocuriePerMilliliter (0 members)
- Assumption (1 member)
- Resolution (2 members)
- Wood (0 members)
- Terajoule (0 members)
- SecondaryEnergyCarrierDisposition (0 members)
- DeliveryTimePoint (0 members)
- PixelsPerMillimeter (0 members)
- ElectricalEnergyStorageFunction (0 members)
- EducationalOrganization (1 member)
- BinaryFileFormat (0 members)
- Chain (0 members)
- OeoTerm (0 members)
- GreenhouseGas (4 members)
- Dauer (0 members)
- Biomethane (1 member)