The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Helicopter (0 members)
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- OwlClass (2 members)
- UncertaintyApproach (0 members)
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- Milli (0 members)
- FeretDiameter (0 members)
- SpecificSpaceRequirement (0 members)
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- PrefectFlow (0 members)
- OSW7320196c95834b15974ec1f5c86737cd (1 member)
- DevelopableFlowPotential (0 members)
- Centimeter (0 members)
- Receiver (0 members)
- SingleAxisTrackedReceivingSurface (0 members)
- EndogenousData (1 member)
- StudyRegion (0 members)
- WindFarm (2 members)
- BatteryPassportCatenaXV600 (3 members)
- Boiler (0 members)
- VariableProductionCost (0 members)
- TechnologicalFlowPotential (0 members)
- HydroelectricEnergyTransformation (3 members)
- ZeroDimensionalTemporalRegion (4 members)
- Geogenic (1 member)
- SquareMicrometer (0 members)
- PowerToLiquidProcess (0 members)
- Acoustical (0 members)
- DataAcquisitionRate (0 members)
- ElectricalEnergyShareValue (0 members)
- Location (0 members)
- ConfluencePercentage (0 members)
- AreaUnit (10 members)
- PumpedHydroEnergy (0 members)
- DirectiveInformationEntity (1 member)
- PowerPlantWithElectroMotiveGenerator (9 members)
- Femtoliter (0 members)
- MicrogramPerLiter (0 members)
- ParticleNumber (0 members)
- Nanometer (0 members)
- LatentHeatStorageObject (2 members)
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- Software (2 members)
- AngularVelocityUnit (1 member)
- Nanomolal (0 members)
- WaterElectrolysisProcess (0 members)
- HeatTransfer (4 members)
- FootCandle (0 members)
- ResearchOrganization (0 members)