The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- BatteryElectricCar (1 member)
- GramPerLiter (0 members)
- RelationalQuality (0 members)
- Author (0 members)
- GaseousBiofuel (2 members)
- CarbonDioxideEquivalentQuantity (0 members)
- CrfBasedSectorDivision (1 member)
- Photon (0 members)
- FossilEnergy (0 members)
- MaterialRelated (6 members)
- BiofuelPowerPlant (2 members)
- DataProcessingSoftware (0 members)
- Rock (0 members)
- BiogenicMunicipalWasteFuel (0 members)
- CompressedAir (0 members)
- ObsolescenceReasonSpecification (0 members)
- Synthetic (0 members)
- BasePair (3 members)
- Hydrocarbon (1 member)
- NitrogenDioxide (0 members)
- LiquidCombustionFuel (5 members)
- PlanSpecification (8 members)
- SolarThermalCollector (2 members)
- RetortType (0 members)
- PersonalLivingSpace (0 members)
- Task (1 member)
- FreightPort (0 members)
- Room (0 members)
- RuralPopulation (0 members)
- Person (0 members)
- DehngrenzeBeiPlastischerExtensometerDehnungRp01 (0 members)
- TransportHub (4 members)
- Weber (0 members)
- SourceCodeFileFormat (0 members)
- DehngrenzeBeiPlastischerExtensometerDehnung (2 members)
- Minute (0 members)
- WasteAndWastewaterSector (0 members)
- SpatialResolutionUnit (4 members)
- EditorsOntologyModule (0 members)
- SectoralEnergyConsumption (0 members)
- Kelvin (0 members)
- Picomolal (0 members)
- ConsideredRegion (0 members)
- CompressedGasVehicle (2 members)
- Water (2 members)
- MetaFundamentalQuantityValue (0 members)
- PowerToLiquidSystem (0 members)
- OSWc848187430df5690bc1aba81691b3689 (1 member)
- FuelPoweredElectricityGenerationProcess (1 member)
- WindEnergy (0 members)