The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- FirstCharge (0 members)
- PotassiumTetrafluoroborate (0 members)
- PrefixedUnit (270 members)
- PolymerElectrolyte (0 members)
- NuclearQuadrupoleMoment (0 members)
- PotassiumSaltCompound (18 members)
- CouplingFactor (0 members)
- AttoJouleSecond (0 members)
- KiloJoulePerMole (0 members)
- MicroMole (0 members)
- FunctionalIcon (3 members)
- GramPerKilogram (0 members)
- Dismantling (0 members)
- TemperaturePerSquareTimeUnit (1 member)
- SampleExtractionByCutting (0 members)
- LithiumSulfate (0 members)
- IronDisulfide (0 members)
- KelvinSquareMetrePerKilogramPerSecond (0 members)
- SinusoidalPotentialWaveform (0 members)
- Graphical (3 members)
- SpecificPower (0 members)
- AstatineSymbol (0 members)
- Particle size distribution (additives) (0 members)
- NPropanol (0 members)
- Thickness gauge (0 members)
- Soldering (0 members)
- RhodiumIIIOxide (0 members)
- DischargingVoltage (1 member)
- Beryllium (0 members)
- RhodiumOxideCompound (2 members)
- ComplexPower (0 members)
- Sawing (0 members)
- Join (0 members)
- Calendering (0 members)
- RubidiumAtom (0 members)
- Suspension density (0 members)
- GraphiteElectrode (0 members)
- Pressure of the rolls (calendering) (0 members)
- PicoGramPerGram (0 members)
- PerforatedFoil (0 members)
- Optical Profilometry (0 members)
- D40ParticleSize (0 members)
- PowerUnit (17 members)
- CommandLanguage (1 member)
- CentiMetrePerKelvin (0 members)
- BariumHydroxide (0 members)
- Spin (0 members)
- ModulusOfRigidity (0 members)
- CathodicProtection (0 members)
- VolumicCrossSection (0 members)