The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.

• 1P-LSD (1 member)
• 3-Me-PCP (1 member)
• 3-Me-PCPy (1 member)
• 3-MeO-PCE (1 member)
• 3-MeO-PCMo (1 member)
• 3-MeO-PCP (1 member)
• 4-AcO-DMT (1 member)
• 4-MeO-PCP (1 member)
• 5-MeO-DMT (1 member)
• ALD-52 (1 member)
• Acetylcholinesterase inhibitor (3 members)
• Actoprotector (1 member)
• Adamantane (2 members)
• Alcohol (1 member)
• Alkaloid (4 members)
• Alkaloids (1 member)
• All articles with unsourced statements (39 members)
• All pages needing cleanup (1 member)
• Amanita (genus) (1 member)
• Amanita muscaria (1 member)
• Amantadine (1 member)
• Amphetamine (1 member)
• Analgesics (4 members)
• Anaphrodisiac (1 member)
• Anilidopiperidine (3 members)
• Anti-inflammatory and antirheumatic products (2 members)
• Antidepressant (0 members)
• Antipsychotic (1 member)
• Anxiogenic (0 members)
• Anxiolytics (0 members)
• Aphrodisiac (0 members)
• Apocynaceae (family) (1 member)
• Approval (17 members)
• Article without enough references (2 members)
• Articles in talk page (2 members)
• Articles with invalid date parameter in template (18 members)
• Articles with unsourced statements (21 members)
• Articles with unsourced statements from December 2022 (1 member)
• Arylcyclohexylamine (15 members)
• Atypical Neuroleptic (1 member)
• Ayahuasca (1 member)
• Base Structures (1 member)
• Benzamide (2 members)
• Benzimidazole (1 member)
• Benzimidazolone (1 member)
• Benzodiazepine (1 member)
• Benzodiazepines (2 members)
• Benzofuran (5 members)
• Beta-Carboline (2 members)
• Botany (1 member)