The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Nanometer (0 members)
- LatentHeatStorageObject (2 members)
- NaturalGasTurbine (0 members)
- PlateHeatExchanger (0 members)
- Software (2 members)
- AngularVelocityUnit (1 member)
- Nanomolal (0 members)
- WaterElectrolysisProcess (0 members)
- HeatTransfer (4 members)
- FootCandle (0 members)
- ResearchOrganization (0 members)
- SodiumIonBattery (0 members)
- OSW78afa9d96cd95972af391622dd3b13b8 (1 member)
- UnitOfMolality (7 members)
- TargetDrivenScenario (0 members)
- Genauigkeit (0 members)
- Gigabasepair (0 members)
- CarbonDioxide (0 members)
- FinalGaugeLengthAfterFracture (0 members)
- MetricTon (0 members)
- Coulomb (0 members)
- Micro (0 members)
- Vehicle (8 members)
- Hecto (0 members)
- GeothermalHeatTransfer (0 members)
- MassUnit (20 members)
- SubsurfaceCollector (0 members)
- SurfaceAzimuthAngle (0 members)
- ElectricityCost (0 members)
- SectorDivision (5 members)
- SolarElectricalEnergy (0 members)
- TestOntologyClassA12 (0 members)
- IlluminanceUnit (2 members)
- CarbonCaptureAndStorage (0 members)
- MillionTonOfOilEquivalent (0 members)
- NewtonPerMeter (0 members)
- MyDataset (1 member)
- Microvolt (0 members)
- CompressedSyntheticMethane (0 members)
- BigMapBatteryCell (3 members)
- ArealEnergyDensityUnit (0 members)
- SolarReceivingObject (8 members)
- Millimole (0 members)
- DimensionMeasuringDevice (0 members)
- CompressedAirEnergyStorageUnit (1 member)
- TensileTestInAccordanceWithIso68921 (0 members)
- ConcentrationUnit (18 members)
- FrequencyControl (3 members)
- MolarVolumeUnit (2 members)
- Symbol (2 members)