The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Picoliter (0 members)
- VehicleKilometre (0 members)
- PowerToMethaneSystem (0 members)
- GridTransferredThermalEnergy (0 members)
- DeliveryInterval (0 members)
- Gasoline (2 members)
- DataTool (0 members)
- Radian (0 members)
- SemiCrystallineStructure (0 members)
- Time (0 members)
- FuelCellElectricTruck (0 members)
- GasolineEngine (0 members)
- Perfluorocarbon (0 members)
- Demand (2 members)
- AgricultureForestryAndLandUseSector (0 members)
- BaseFraction (0 members)
- ParallelLength (0 members)
- EnergyUnit (21 members)
- GramPerMole (0 members)
- SensibleHeatStorageObject (2 members)
- NetCapacityFactor (0 members)
- Bit (0 members)
- ConditioningProcess (2 members)
- Origin (5 members)
- ArealPowerDensityUnit (0 members)
- DecarbonisationPathway (0 members)
- KilogramPerMole (0 members)
- LandVehicle (2 members)
- PotentialEnergy (0 members)
- EnergyBalanceCalculationMethod (0 members)
- MilliunitsPerMilliliter (0 members)
- FuelMarketExchange (0 members)
- Biodiesel (0 members)
- DiffuseSolarRadiation (0 members)
- Lignite (0 members)
- VolumeUnit (25 members)
- SoftwareDeveloper (0 members)
- RelativeFluorescenceUnit (0 members)
- Mineral (1 member)
- SyntheticDataSet (0 members)
- InstallationGuide (0 members)
- Pump (0 members)
- WeatherTimeSeries (0 members)
- DimensionlessUnit (7 members)
- AngularAccelerationUnit (1 member)
- ChromaSamplingUnit (0 members)
- WorkingAgePopulation (0 members)
- Abbreviation (1 member)
- Paper (0 members)
- Heater (5 members)