The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- ConstantCurrentCharging (1 member)
- Prismatic (0 members)
- Near IR (0 members)
- MobiusStrip (0 members)
- PercentUnit (0 members)
- ManganeseIISulfide (0 members)
- MilliSievert (0 members)
- MassTemperatureUnit (2 members)
- Gap height (0 members)
- ProcessByContext (4 members)
- LithiumAcetate (0 members)
- CalciumPhosphate (0 members)
- MetrologicalUncertainty (0 members)
- AbsorbedDoseUnit (13 members)
- ZincOxide (0 members)
- DynamicLightScattering (0 members)
- ThuliumSymbol (0 members)
- Particle size distribution (active materials) (0 members)
- GramPerCubicDeciMetre (0 members)
- MonoblocBattery (0 members)
- SurfaceA3B (0 members)
- AtomisticModel (0 members)
- ConstantPotentialPulses (0 members)
- LengthTimeCurrentUnit (1 member)
- Caesium (0 members)
- Frequency (6 members)
- Replica (0 members)
- TotalMassLoading (0 members)
- Self-Discharge Testing and Evaluation (0 members)
- XrayDiffraction (1 member)
- SpecificEnthalpy (0 members)
- HectoPascalCubicMetrePerSecond (0 members)
- WattPerSquareMetreSteradian (0 members)
- Tungsten (0 members)
- CaesiumAtom (0 members)
- Pre-mixing (0 members)
- CarbonCloth (0 members)
- VolumePerTemperatureUnit (2 members)
- StepDuration (0 members)
- Mega (0 members)
- End of charge voltage (0 members)
- pH Meter (0 members)
- Torus (0 members)
- Sulfolane (0 members)
- CapacitancePerLengthUnit (0 members)
- Web Guiding Systems (0 members)
- QuarticLengthUnit (2 members)
- MinimumStoichiometricCoefficient (0 members)
- NanoGramPerSquareMetrePerPascalPerSecond (0 members)
- Foaming (0 members)