The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- (Neder)brackets (1 member)
- *Fix me! (2 members)
- 0-9 (0 members)
- ??? (11 members)
- A (1 member)
- ABBYY Lingvo (1 member)
- ADP (1 member)
- AGROVOC (2 members)
- AIRGLOSS (1 member)
- AIVC (1 member)
- AMTS (3 members)
- ANNEX 31 (1 member)
- Abbreviation (1 member)
- Abbreviations (108 members)
- Accounting (1 member)
- Acronymbook (8 members)
- Acronymbook.com (8 members)
- Afrikaans (5 members)
- Agriculture (4 members)
- Air conditioning (2 members)
- Alpex (1 member)
- Alternative medicine (1 member)
- Amazon (2 members)
- American Mathematical Society (1 member)
- Amo (1 member)
- Amsterdam Airport Schiphol (1 member)
- Animal adjectives (1 member)
- Animals (2 members)
- Antalis (1 member)
- Antiquarian booksellers (1 member)
- Apple (4 members)
- Aquo-lex (1 member)
- Architecture (1 member)
- Archiving (2 members)
- Armed forces (4 members)
- Automotive (13 members)
- Avans University of Applied Sciences (1 member)
- Aviation (6 members)
- B (0 members)
- BEIJER.rystb (7 members)
- BOA (1 member)
- Baking (1 member)
- Ballooning (1 member)
- Banking (2 members)
- Beer (1 member)
- Beer brewing (1 member)
- Beijer.bot (1 member)
- Beijerdeas (1 member)
- Beijerterm.com (1 member)
- Beijerterm.com/archives (1 member)