The Bluelight community can assist with this question!
Recently my colleagues and I created the following list, which we think is fairly inclusive. Be keen to hear if there's any drug classes anyone reading believes we have left off.
Alcohol
Tobacco
E-cigarette/vaping device that contains nicotine
Cannabis and cannabis products
MDMA/Ecstasy/Molly
Cocaine
Amphetamine
Methamphetamine
Ketamine
GHB/GBL/1,4-butanediol
Nitrous oxide
Amyl nitrite
LSD
2C-B
Other 2C series (C, E, I etc)
Magic mushrooms (psilocybin)
DMT
Other tryptamines (4-AcO-DMT, 5-MeO-DMT, AMT etc)
Prescription benzodiazepines (diazepam, temazepam etc)
Prescription z-drugs (zolpidem, zopiclone etc)
Prescription opioids (oxycontin, morphine, fentanyl etc)
Prescription stimulants (methylphenidate/ritalin, modafinil etc)
Heroin
Synthetic cathinones (ethylone, n-ethyl-pentylone etc)
Other novel stimulants (4-FA, 2-FA etc)
Novel dissociatives (FXE, 2-FDCK etc)
NBOMe series (25I, 25C, 25B etc)
LSD analogues (1P-LSD, ETH-LAD, AL-LAD etc)
Novel benzodiazepines (etizolam, phenazepam etc)
Novel opioids (fentanyl analogues etc)
Synthetic cannabinoids
Anabolic-androgenic steroids
Other drug type/s - please specify