Will-O-Wisp is learned by 28 species by level, 130 by machine and 4 by egg

Effect, in PokéAPI's words

“Burns the target.”

Who learns it

130 species in all, 6 of 18 games shown

Scarlet and Violet: 106 species

Species	Method	Level
Chandelure	Level up, Machine	1
Chi-Yu	Level up, Machine	15
Shuppet	Level up, Machine	16
Banette	Level up, Machine	16
Phantump	Level up, Machine	16
Trevenant	Level up, Machine	16
Charcadet	Level up, Machine	16
Armarouge	Level up, Machine	16
Ceruledge	Level up, Machine	16
Litwick	Level up, Machine	20
Lampent	Level up, Machine	20
Vulpix	Level up, Machine	24
Duskull	Level up, Machine	24
Dusclops	Level up, Machine	24
Dusknoir	Level up, Machine	24
Fennekin	Level up, Machine	38
Crocalor	Level up, Machine	42
Braixen	Level up, Machine	45
Froslass	Level up, Machine	47
Skeledirge	Level up, Machine	47
Delphox	Level up, Machine	51
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Ninetales	Machine
Growlithe	Machine
Arcanine	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Koffing	Machine
Weezing	Machine
Magmar	Machine
Flareon	Machine
Moltres	Machine
Mewtwo	Machine
Mew	Machine
Cyndaquil	Machine
Quilava	Machine
Typhlosion	Machine
Misdreavus	Machine
Slugma	Machine
Magcargo	Machine
Houndour	Machine
Houndoom	Machine
Magby	Machine
Entei	Machine
Ho-Oh	Machine
Torchic	Machine
Combusken	Machine
Blaziken	Machine
Shiftry	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Sableye	Machine
Numel	Machine
Camerupt	Machine
Torkoal	Machine
Altaria	Machine
Groudon	Machine
Chimchar	Machine
Monferno	Machine
Infernape	Machine
Drifloon	Machine
Drifblim	Machine
Mismagius	Machine
Spiritomb	Machine
Magmortar	Machine
Gallade	Machine
Rotom	Machine
Heatran	Machine
Giratina	Machine
Darkrai	Machine
Arceus	Machine
Tepig	Machine
Pignite	Machine
Emboar	Machine
Larvesta	Machine
Volcarona	Machine
Reshiram	Machine
Fletchinder	Machine
Talonflame	Machine
Litleo	Machine
Pyroar	Machine
Volcanion	Machine
Litten	Machine
Torracat	Machine
Incineroar	Machine
Salandit	Machine
Salazzle	Machine
Mimikyu	Machine
Lunala	Machine
Cinderace	Machine
Rolycoly	Machine
Carkol	Machine
Coalossal	Machine
Sinistea	Machine
Polteageist	Machine
Drakloak	Machine
Dragapult	Machine
Spectrier	Machine
Fuecoco	Machine
Scovillain	Machine
Houndstone	Machine
Slither Wing	Machine

Brilliant Diamond and Shining Pearl: 61 species

Species	Method	Level
Ninetales	Level up, Machine	1
Shuppet	Level up, Machine	16
Banette	Level up, Machine	16
Vulpix	Level up, Machine	24
Duskull	Level up, Machine	24
Dusclops	Level up, Machine	24
Dusknoir	Level up, Machine	24
Froslass	Level up, Machine	47
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Growlithe	Machine
Arcanine	Machine
Ponyta	Machine
Rapidash	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Koffing	Machine
Weezing	Machine
Magmar	Machine
Flareon	Machine
Moltres	Machine
Mewtwo	Machine
Mew	Machine
Cyndaquil	Machine
Quilava	Machine
Typhlosion	Machine
Misdreavus	Machine
Slugma	Machine
Magcargo	Machine
Houndour	Machine
Houndoom	Machine
Magby	Machine
Entei	Machine
Ho-Oh	Machine
Torchic	Machine
Combusken	Machine
Blaziken	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Shedinja	Machine
Sableye	Machine
Numel	Machine
Camerupt	Machine
Torkoal	Machine
Solrock	Machine
Absol	Machine
Chimchar	Machine
Monferno	Machine
Infernape	Machine
Drifloon	Machine
Drifblim	Machine
Mismagius	Machine
Spiritomb	Machine
Magmortar	Machine
Gallade	Machine
Rotom	Machine
Heatran	Machine
Giratina	Machine

Sword and Shield: 88 species

Species	Method	Level
Ninetales	Level up, Machine	1
Chandelure	Level up, Machine	1
Yamask	Level up, Machine	16
Cofagrigus	Level up, Machine	16
Phantump	Level up, Machine	16
Trevenant	Level up, Machine	16
Litwick	Level up, Machine	20
Lampent	Level up, Machine	20
Vulpix	Level up, Machine	24
Duskull	Level up, Machine	24
Dusclops	Level up, Machine	24
Dusknoir	Level up, Machine	24
Froslass	Level up, Machine	47
Blacephalon	Level up, Machine	55
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Growlithe	Machine
Arcanine	Machine
Ponyta	Machine
Rapidash	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Koffing	Machine
Weezing	Machine
Magmar	Machine
Flareon	Machine
Moltres	Machine
Mewtwo	Machine
Mew	Machine
Magby	Machine
Entei	Machine
Ho-Oh	Machine
Torchic	Machine
Combusken	Machine
Blaziken	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Shedinja	Machine
Sableye	Machine
Torkoal	Machine
Solrock	Machine
Absol	Machine
Drifloon	Machine
Drifblim	Machine
Spiritomb	Machine
Magmortar	Machine
Gallade	Machine
Rotom	Machine
Heatran	Machine
Giratina	Machine
Victini	Machine
Darumaka	Machine
Darmanitan	Machine
Frillish	Machine
Jellicent	Machine
Heatmor	Machine
Larvesta	Machine
Volcarona	Machine
Reshiram	Machine
Fletchling	Machine
Fletchinder	Machine
Talonflame	Machine
Pumpkaboo	Machine
Gourgeist	Machine
Volcanion	Machine
Litten	Machine
Torracat	Machine
Incineroar	Machine
Salandit	Machine
Salazzle	Machine
Turtonator	Machine
Mimikyu	Machine
Lunala	Machine
Marshadow	Machine
Rolycoly	Machine
Carkol	Machine
Coalossal	Machine
Centiskorch	Machine
Sinistea	Machine
Polteageist	Machine
Cursola	Machine
Runerigus	Machine
Drakloak	Machine
Dragapult	Machine
Spectrier	Machine

Let's Go Pikachu and Let's Go Eevee: 19 species

Species	Method	Level
Gastly	Level up, Machine	14
Haunter	Level up, Machine	14
Gengar	Level up, Machine	14
Vulpix	Level up, Machine	17
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Ninetales	Machine
Growlithe	Machine
Arcanine	Machine
Ponyta	Machine
Rapidash	Machine
Koffing	Machine
Weezing	Machine
Magmar	Machine
Flareon	Machine
Moltres	Machine
Mewtwo	Machine
Mew	Machine

Ultra Sun and Ultra Moon: 104 species

Species	Method	Level
Shuppet	Level up, Machine	16
Banette	Level up, Machine	16
Litwick	Level up, Machine	16
Lampent	Level up, Machine	16
Vulpix	Level up, Machine	20
Yamask	Level up, Machine	21
Cofagrigus	Level up, Machine	21
Duskull	Level up, Machine	25
Dusclops	Level up, Machine	25
Dusknoir	Level up, Machine	25
Froslass	Level up, Machine	28
Phantump	Level up, Machine	31
Trevenant	Level up, Machine	31
Fennekin	Level up, Machine	38
Braixen	Level up, Machine	45
Delphox	Level up, Machine	51
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Ninetales	Machine
Growlithe	Machine
Arcanine	Machine
Ponyta	Machine
Rapidash	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Koffing	Machine
Weezing	Machine
Magmar	Machine
Flareon	Machine
Moltres	Machine
Mewtwo	Machine
Mew	Machine
Cyndaquil	Machine
Quilava	Machine
Typhlosion	Machine
Misdreavus	Machine
Slugma	Machine
Magcargo	Machine
Houndour	Machine
Houndoom	Machine
Magby	Machine
Entei	Machine
Ho-Oh	Machine
Torchic	Machine
Combusken	Machine
Blaziken	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Shedinja	Machine
Sableye	Machine
Numel	Machine
Camerupt	Machine
Torkoal	Machine
Solrock	Machine
Absol	Machine
Chimchar	Machine
Monferno	Machine
Infernape	Machine
Drifloon	Machine
Drifblim	Machine
Mismagius	Machine
Spiritomb	Machine
Magmortar	Machine
Gallade	Machine
Rotom	Machine
Heatran	Machine
Giratina	Machine
Darkrai	Machine
Arceus	Machine
Victini	Machine
Tepig	Machine
Pignite	Machine
Emboar	Machine
Pansear	Machine
Simisear	Machine
Darumaka	Machine
Darmanitan	Machine
Frillish	Machine
Jellicent	Machine
Chandelure	Machine
Heatmor	Machine
Larvesta	Machine
Volcarona	Machine
Reshiram	Machine
Fletchinder	Machine
Talonflame	Machine
Litleo	Machine
Pyroar	Machine
Pumpkaboo	Machine
Gourgeist	Machine
Volcanion	Machine
Litten	Machine
Torracat	Machine
Incineroar	Machine
Salandit	Machine
Salazzle	Machine
Turtonator	Machine
Mimikyu	Machine
Lunala	Machine
Marshadow	Machine
Blacephalon	Machine

Sun and Moon: 103 species

Species	Method	Level
Shuppet	Level up, Machine	16
Banette	Level up, Machine	16
Litwick	Level up, Machine	16
Lampent	Level up, Machine	16
Vulpix	Level up, Machine	20
Yamask	Level up, Machine	21
Cofagrigus	Level up, Machine	21
Duskull	Level up, Machine	25
Dusclops	Level up, Machine	25
Dusknoir	Level up, Machine	25
Froslass	Level up, Machine	28
Phantump	Level up, Machine	31
Trevenant	Level up, Machine	31
Fennekin	Level up, Machine	38
Braixen	Level up, Machine	45
Delphox	Level up, Machine	51
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Ninetales	Machine
Growlithe	Machine
Arcanine	Machine
Ponyta	Machine
Rapidash	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Koffing	Machine
Weezing	Machine
Magmar	Machine
Flareon	Machine
Moltres	Machine
Mewtwo	Machine
Mew	Machine
Cyndaquil	Machine
Quilava	Machine
Typhlosion	Machine
Misdreavus	Machine
Slugma	Machine
Magcargo	Machine
Houndour	Machine
Houndoom	Machine
Magby	Machine
Entei	Machine
Ho-Oh	Machine
Torchic	Machine
Combusken	Machine
Blaziken	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Shedinja	Machine
Sableye	Machine
Numel	Machine
Camerupt	Machine
Torkoal	Machine
Solrock	Machine
Absol	Machine
Chimchar	Machine
Monferno	Machine
Infernape	Machine
Drifloon	Machine
Drifblim	Machine
Mismagius	Machine
Spiritomb	Machine
Magmortar	Machine
Gallade	Machine
Rotom	Machine
Heatran	Machine
Giratina	Machine
Darkrai	Machine
Arceus	Machine
Victini	Machine
Tepig	Machine
Pignite	Machine
Emboar	Machine
Pansear	Machine
Simisear	Machine
Darumaka	Machine
Darmanitan	Machine
Frillish	Machine
Jellicent	Machine
Chandelure	Machine
Heatmor	Machine
Larvesta	Machine
Volcarona	Machine
Reshiram	Machine
Fletchinder	Machine
Talonflame	Machine
Litleo	Machine
Pyroar	Machine
Pumpkaboo	Machine
Gourgeist	Machine
Volcanion	Machine
Litten	Machine
Torracat	Machine
Incineroar	Machine
Salandit	Machine
Salazzle	Machine
Turtonator	Machine
Mimikyu	Machine
Lunala	Machine
Marshadow	Machine

Changed over time

One change since Generation III

1. Through Gen VAccuracy 75%85% from X and Y, Generation VI