The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- PrimaryEnergyCarrierHarvest (0 members)
- Pm10 (0 members)
- CrystallineStructure (0 members)
- OwlIndividual (0 members)
- MeasurementDevice (0 members)
- PlaneAngleUnit (2 members)
- Ph (0 members)
- DischargeRate (0 members)
- OntologyModuleSubsettedByOwlProfile (1 member)
- Floor (0 members)
- TonOfCoalEquivalent (0 members)
- Quality (9 members)
- GeneratedOntologyModule (1 member)
- Ton (0 members)
- DirectAirCapture (0 members)
- FragmentSelector (0 members)
- SpeedVelocityUnit (3 members)
- DisintegrationsPerSecond (0 members)
- PowerGeneratingUnit (16 members)
- SuperconductingMagneticEnergyStorage (0 members)
- PartsPerBillion (0 members)
- Co2EmissionCertificatePrice (0 members)
- BleibendeExtensometerDehnung (0 members)
- SquareMeter (0 members)
- HardCoalPowerPlant (0 members)
- Attomole (0 members)
- GasTurbine (3 members)
- KilogramPerMeter (0 members)
- HeatPump (1 member)
- CrossSectionArea (0 members)
- AdiabaticEnergyStorageObject (0 members)
- EnergySystemModel (0 members)
- OntologyRelated (0 members)
- Oxygen (0 members)
- Acronym (0 members)
- AusrichtungDerHalterungen (0 members)
- FuelCellElectricCar (0 members)
- EnergyTransformationSector (2 members)
- TransformativeAnalysisProcess (0 members)
- EndingTime (0 members)
- GasolineFuelRole (0 members)
- Höchstkraft (0 members)
- PowerPlantOperator (0 members)
- DecommissioningCost (0 members)
- ConventionalEnergy (5 members)
- CreativeWork (2 members)
- TurbidityUnit (1 member)
- LifeTime (1 member)
- BaseUnitOfMeasure (6 members)
- Co2Price (1 member)