I don't know if I can choose a top 5.
By all rights caffeine, ethanol and cannabis deserve to be there.
Mescaline or 4-AcO-xxT would definitely place.
I think MDMA and MXE probably also tie for a place.
It's too difficult to choose tbh it depends what I'm feeling.
Honorable mentions to go to ketamine, mephedrone, miprocin, moxy, 4-FA.
Some people may ask why mescaline and 4-AcO, but not N,N-DMT or LSD? Purely personal preference.
Here the list so far ;)
Depressants & Dissociatives;
Ethanol / drinking alcohol
(3-methylbutyl) nitrite / Amyl Nitrite / Poppers
β-Phenyl-γ-aminobutyric acid / PhGABA / Phenibut
γ-Hydroxybutyric acid / GHB / G, fantasy
Morphine / Opium
Thebaine / Paramorphine
Codeine / 3-Methylmorphine
Dihydrocodeine / DHC
Tramadol / Ultram
Chlordiazepoxide / Librium
Diazepam / Valium
2'-Chlorodiazepam / Ro5-3448 / Diclazepam
4'-Chlorodiazepam / Ro5-4864
Alprazolam / Xanax
Clonazolam, Clonitrazolam / Clam
Etizolam / Etilaam, Etizest
Quetiapine / Seroquel
Thiopental / Sodium Pentothal
Promethazine / Phenergan
Nitrous Oxide / N2O / NOs, laughing gas
Ketamine [racemic] / K, Kitty
Esketamine [S-isomer] / Special K
Deschloroketamine / 2'-Oxo-PCM / DXE / DCK
Methoxetamine / 3-MeO-2'-Oxo-PCE / MXE / Mexxy
3-Methoxyphencyclidine / 3-MeO-PCP
Zopiclone / Zimovane
Stimulants & Nootropics;
Benzoylmethylecgonine / Cocaine / Charlie, nose candy
1,3,7-Trimethylpurine-2,6-dione / Caffeine / Coffee, Black Tea
N-Ethyl-L-glutamine / L-Theanine / [constituent of] Green Tea
3,7-dimethylxanthine / Theobromine / [constituent of] Chocolate
2-Hydroxy-N,N,N-trimethylethan-1-aminium / Choline bitartrate
L-alpha glycerylphosphorylcholine / Alpha-GPC, Choline alfoscerate
Cytidine 5'-diphosphocholine / CDP-choline, Citicoline
2-Dimethylaminoethyl (4-chlorophenoxy)acetate / Meclofenoxate
N-Phenylacetyl-L-prolylglycine ethyl ester / Noopept
Coluracetam / BCI-540
(R,S)-2-(2-oxo-4-phenylpyrrolidin-1-yl)acetamide / 4-Phenylpiracetam
(RS)-1-(1-methylethylamino)-3-(1-naphthyloxy)propan-2-ol / Propranolol
(±)-2-Benzhydrylsulfinylethanehydroxamic acid / Adrafinil
(±)-2-[(Diphenylmethyl)sulfinyl]acetamide / Modafinil
(–)-2-[(R)-(diphenylmethyl)sulfinyl]acetamide / Armodafinil
(S)-3-[1-Methylpyrrolidin-2-yl]pyridine / Nicotine / Tobacco
3,4,8-Trimethoxyphenanthrene-2,5-diol / Dendrobium Nobile
Mesembrine / Sceletium Tortuosum, Kanna
3,4-Methylenedioxymethamphetamine / MDMA / Molly, Mandy, ecstasy
3,4-Methylenedioxymethcathinone / MDMC / βk-MDMA / Methylone
β-Keto-methylbenzodioxolylpentanamine / βk-MBDP / Pentylone
α-Methylphenethylamine / αMP / Amphetamines / Speed
4-Fluoroamphetamine / 4-FMP, 4-FA / PAL-303 / Flux
2-Fluoromethamphetamine / 2-FMA
4-Methoxyamphetamine / PMA, 4-MA / Death
3-Methylmethcathinone / 3-MMC / Metaphedrone
4-Methylmethcathinone / 4-MMC / Mephedrone
4-Methylethcathinone / 4-MEC
4-Chloromethcathinone / 4-CMC / Clephedrone
4-Fluoromethcathinone / 4-FMC / Flephedrone
4-Fluoro-α-methylaminovalerophenone / 4-Fluoropentedrone / 4-FPD
α-Ethylaminocaprophenone / N-Ethylhexedrone / NEH / Hexen
4-desoxy-MDA / 6-(2-Aminopropyl)-2,3-dihydrobenzofuran / 6-APDB
4-chloro-N-(2-morpholin-4-ylethyl)benzamide / Moclobemide
5-Hydroxytryptophan / 5-HTP / Oxitryptan
Escitalopram / Cipralex, Lexapro
Fluoxetine / Prozac
Tianeptine / Coaxil, Stablon, Tatinol
Venlafaxine / Effexor
Hallucinogens & Psychedelics;
Δ9-Tetrahydrocannabinol / THC / Cannabis Sativa/Indica, Marijuana
Cannabidiol / CBD / Herbal Cannabis, Cannabis Resin
AM-2201 / Synth-'noid, Spice
NM-2201 / CBL-2201
5C-AB-PINICA
Harmine / Peganum Harmala / Syrian Rue
Salvinorin A / Salvia Divinorum / Diviner's Sage
d-Lysergic acid amide / d-Lysergamide / LSA / Ergine
Lysergic acid diethylamide / Lysergide / LSD / Acid, Lucy
1-Acetyl-lysergic acid diethylamide / 1A-LSD / ALD-52
1-Propionyl-lysergic acid diethylamide / 1P-LSD
2,5-Dimethoxy-4-methylamphetamine / DOM / Dominic
2,5-Dimethoxy-4-chloroamphetamine / DOC / Doctor
2,5-Dimethoxy-4-methylthioamphetamine / DOT / Aleph
2,5-Dimethoxy-4-iodophenethylamine / 2C-I / Infinity
2,5-Dimethoxy-4-ethylphenethylamine / 2C-E / Eternity
2,5-Dimethoxy-4-bromophenethylamine / 2C-B / Nexus
2,5-Dimethoxy-4-methylthiophenethylamine / 2C-T / Tesseract
2,5-Dimethoxy-4-ethylthiophenethylamine / 2C-T-2 / Rosy
2,5-Dimethoxy-4-fluoroethylthiophenethylamine / 2C-T-21 / Aurora
2,5-Dimethoxy-4-bromo-β-keto-phenethylamine / βk-2C-B
2,3,6,7-Benzo-dihydro-difuran-8-bromo-ethylamine / 2C-B-FLY
2,5-Dimethoxy-N-(2-methoxybenzyl)-4-bromophenethylamine / 25B
2,5-Dimethoxy-N-(2-methoxybenzyl)-4-chlorophenethylamine / 25C
2,5-Dimethoxy-N-(2-methoxybenzyl)-4-iodophenethylamine / 25I
3,4-Methylenedioxyamphetamine / MDA / Sass, Sally
3,4,5-Trimethoxyphenethylamine / Mescaline / M
3,5-Dimethoxy-4-methallyloxyphenethylamine / Methallylescaline / MAL
N,N-dimethyltryptamine / DMT / The Spirit / Dmitri
N,N-dipropyltryptamine / DPT / The Light
N-Methyl-N-ethyltryptamine / MET / The Colour
N-Methyl-N-isopropyltryptamine / MiPT / The Touch
4-Hydroxy-dimethyltryptamine / 4-HO-DMT / Psilocin
4-Acetoxy-dimethyltryptamine / 4-AcO-DMT / Psilacetin
4-Hydroxy-N-methyl-N-ethyltryptamine / 4-HO-MET / Metocin
4-Acetoxy-N-methyl-N-ethyltryptamine / 4-AcO-MET / Metacetin
4-Phosphoryloxy-N,N-dimethyltryptamine / 4-PO-DMT / Psilocybin
4-AcO-N-Me-N-cyclopropyltryptamine / 4-AcO-McPT / Mecypracetin
4-Acetoxy-N-methyl-N-isopropyltryptamine / 4-AcO-MiPT / Mipracetin
4-Hydroxy-N-methyl-N-isopropyltryptamine / 4-HO-MiPT / Miprocin
5-Methoxy-N,N-diallyltryptamine / 5-MeO-DALT / Foxtrot
5-Methoxy-N-methyl-N-isopropyltryptamine / 5-MeO-MiPT / Moxy