Toxic is learned by 62 species by level, 807 by machine and 13 by egg

Effect, in PokéAPI's words

“Badly poisons the target, inflicting more damage every turn.”

Who learns it

807 species in all, 4 of 24 games shown

Scarlet and Violet: 83 species

Species	Method	Level
Vileplume	Level up, Machine	1
Bellossom	Level up, Machine	1
Breloom	Level up, Machine	1
Mandibuzz	Level up, Machine, Egg	1
Eternatus	Level up, Machine	8
Oddish	Level up, Machine	24
Gulpin	Level up, Machine	25
Swalot	Level up, Machine	25
Gloom	Level up, Machine	26
Grimer	Level up, Machine	26
Muk	Level up, Machine	26
Stunky	Level up, Machine	27
Skuntank	Level up, Machine	27
Toxtricity	Level up, Machine	32
Shroomish	Level up, Machine	33
Skrelp	Level up, Machine	35
Dragalge	Level up, Machine	35
Koffing	Level up, Machine	36
Wooper	Level up, Machine	36
Vespiquen	Level up, Machine	36
Croagunk	Level up, Machine	36
Toxicroak	Level up, Machine	36
Foongus	Level up, Machine	36
Amoonguss	Level up, Machine	36
Weezing	Level up, Machine	38
Clodsire	Level up, Machine	40
Qwilfish	Level up, Machine	44
Overqwil	Level up, Machine	44
Quagsire	Level up, Machine	46
Mareanie	Level up, Machine	50
Salandit	Level up, Machine	50
Toxapex	Level up, Machine	56
Pecharunt	Level up, Machine	56
Salazzle	Level up, Machine	58
Bulbasaur	Machine, Egg
Ivysaur	Machine, Egg
Venusaur	Machine, Egg
Ekans	Machine
Arbok	Machine
Venonat	Machine
Venomoth	Machine
Bellsprout	Machine
Weepinbell	Machine
Victreebel	Machine
Tentacool	Machine
Tentacruel	Machine
Gastly	Machine, Egg
Haunter	Machine
Gengar	Machine
Drowzee	Machine
Hypno	Machine
Mew	Machine
Spinarak	Machine
Ariados	Machine
Umbreon	Machine
Dunsparce	Machine
Gligar	Machine
Houndour	Machine
Houndoom	Machine
Seviper	Machine
Spiritomb	Machine
Gliscor	Machine
Zoroark	Machine
Vullaby	Machine, Egg
Sliggoo	Machine
Goodra	Machine
Trevenant	Machine
Sneasler	Machine
Bellibolt	Machine
Shroodle	Machine, Egg
Grafaiai	Machine
Toedscool	Machine, Egg
Toedscruel	Machine
Varoom	Machine, Egg
Revavroom	Machine
Glimmet	Machine, Egg
Glimmora	Machine
Dudunsparce	Machine
Iron Moth	Machine
Okidogi	Machine
Munkidori	Machine
Fezandipiti	Machine
Terapagos	Machine

Brilliant Diamond and Shining Pearl: 38 species

Species	Method	Level
Nidoqueen	Level up, Machine	1
Nidoking	Level up, Machine	1
Vileplume	Level up, Machine	1
Crobat	Level up, Machine	1
Bellossom	Level up, Machine	1
Breloom	Level up	1
Roserade	Level up, Machine	1
Oddish	Level up, Machine	24
Gulpin	Level up, Machine	25
Swalot	Level up, Machine	25
Gloom	Level up, Machine	26
Stunky	Level up, Machine	27
Skuntank	Level up, Machine	27
Dustox	Level up, Machine	32
Shroomish	Level up, Machine	33
Skorupi	Level up, Machine	33
Drapion	Level up, Machine	33
Koffing	Level up, Machine	36
Wooper	Level up, Machine	36
Vespiquen	Level up, Machine	36
Croagunk	Level up, Machine	36
Toxicroak	Level up, Machine	36
Weezing	Level up, Machine	38
Nidoran♀	Level up, Machine	40
Nidoran♂	Level up, Machine	40
Roselia	Level up, Machine	40
Quagsire	Level up, Machine	46
Nidorina	Level up, Machine	50
Nidorino	Level up, Machine	50
Qwilfish	Level up, Machine	52
Bulbasaur	Machine
Ivysaur	Machine
Venusaur	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Mew	Machine
Shuckle	Machine

Sword and Shield: 51 species

Species	Method	Level
Nidoqueen	Level up	1
Nidoking	Level up	1
Vileplume	Level up	1
Crobat	Level up	1
Bellossom	Level up	1
Roserade	Level up	1
Mandibuzz	Level up	1
Eternatus	Level up	8
Oddish	Level up	24
Gloom	Level up	26
Stunky	Level up	27
Skuntank	Level up	27
Trubbish	Level up	30
Garbodor	Level up	30
Toxtricity	Level up	32
Skorupi	Level up	33
Drapion	Level up	33
Skrelp	Level up	35
Dragalge	Level up	35
Koffing	Level up	36
Wooper	Level up	36
Vespiquen	Level up	36
Croagunk	Level up	36
Toxicroak	Level up	36
Venipede	Level up	36
Foongus	Level up	36
Amoonguss	Level up	36
Weezing	Level up	38
Nidoran♀	Level up	40
Nidoran♂	Level up	40
Roselia	Level up	40
Whirlipede	Level up	44
Quagsire	Level up	46
Nidorina	Level up	50
Nidorino	Level up	50
Scolipede	Level up	50
Mareanie	Level up	50
Qwilfish	Level up	52
Accelgor	Level up	52
Salandit	Level up	55
Pyukumuku	Level up	55
Toxapex	Level up	56
Poipole	Level up	63
Naganadel	Level up	63
Salazzle	Level up	65
Bulbasaur	Egg
Gastly	Egg
Shuckle	Egg
Tympole	Egg
Ferroseed	Egg
Vullaby	Egg

Let's Go Pikachu and Let's Go Eevee: 147 species

Species	Method	Level
Nidoran♀	Level up, Machine	18
Nidoran♂	Level up, Machine	18
Gastly	Level up, Machine	21
Haunter	Level up, Machine	21
Gengar	Level up, Machine	21
Nidorina	Level up, Machine	23
Nidorino	Level up, Machine	23
Oddish	Level up, Machine	26
Zubat	Level up, Machine	28
Koffing	Level up, Machine	30
Weezing	Level up, Machine	30
Ekans	Level up, Machine	36
Gloom	Level up, Machine	36
Grimer	Level up, Machine	36
Muk	Level up, Machine	36
Golbat	Level up, Machine	40
Arbok	Level up, Machine	52
Bulbasaur	Machine
Ivysaur	Machine
Venusaur	Machine
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Squirtle	Machine
Wartortle	Machine
Blastoise	Machine
Butterfree	Machine
Beedrill	Machine
Pidgey	Machine
Pidgeotto	Machine
Pidgeot	Machine
Rattata	Machine
Raticate	Machine
Spearow	Machine
Fearow	Machine
Pikachu	Machine
Raichu	Machine
Sandshrew	Machine
Sandslash	Machine
Nidoqueen	Machine
Nidoking	Machine
Clefairy	Machine
Clefable	Machine
Vulpix	Machine
Ninetales	Machine
Jigglypuff	Machine
Wigglytuff	Machine
Vileplume	Machine
Paras	Machine
Parasect	Machine
Venonat	Machine
Venomoth	Machine
Diglett	Machine
Dugtrio	Machine
Meowth	Machine
Persian	Machine
Psyduck	Machine
Golduck	Machine
Mankey	Machine
Primeape	Machine
Growlithe	Machine
Arcanine	Machine
Poliwag	Machine
Poliwhirl	Machine
Poliwrath	Machine
Abra	Machine
Kadabra	Machine
Alakazam	Machine
Machop	Machine
Machoke	Machine
Machamp	Machine
Bellsprout	Machine
Weepinbell	Machine
Victreebel	Machine
Tentacool	Machine
Tentacruel	Machine
Geodude	Machine
Graveler	Machine
Golem	Machine
Ponyta	Machine
Rapidash	Machine
Slowpoke	Machine
Slowbro	Machine
Magnemite	Machine
Magneton	Machine
Farfetch’d	Machine
Doduo	Machine
Dodrio	Machine
Seel	Machine
Dewgong	Machine
Shellder	Machine
Cloyster	Machine
Onix	Machine
Drowzee	Machine
Hypno	Machine
Krabby	Machine
Kingler	Machine
Voltorb	Machine
Electrode	Machine
Exeggcute	Machine
Exeggutor	Machine
Cubone	Machine
Marowak	Machine
Hitmonlee	Machine
Hitmonchan	Machine
Lickitung	Machine
Rhyhorn	Machine
Rhydon	Machine
Chansey	Machine
Tangela	Machine
Kangaskhan	Machine
Horsea	Machine
Seadra	Machine
Goldeen	Machine
Seaking	Machine
Staryu	Machine
Starmie	Machine
Mr. Mime	Machine
Scyther	Machine
Jynx	Machine
Electabuzz	Machine
Magmar	Machine
Pinsir	Machine
Tauros	Machine
Gyarados	Machine
Lapras	Machine
Eevee	Machine
Vaporeon	Machine
Jolteon	Machine
Flareon	Machine
Porygon	Machine
Omanyte	Machine
Omastar	Machine
Kabuto	Machine
Kabutops	Machine
Aerodactyl	Machine
Snorlax	Machine
Articuno	Machine
Zapdos	Machine
Moltres	Machine
Dratini	Machine
Dragonair	Machine
Dragonite	Machine
Mewtwo	Machine
Mew	Machine
Meltan	Machine
Melmetal	Machine

Changed over time

One change since Generation I

1. Through Gen IVAccuracy 85%90% from Black and White, Generation V