Mist is learned by 44 species by level and 26 by egg

Effect, in PokéAPI's words

“Protects the user’s stats from being changed by enemy moves.”

Who learns it

66 species in all, 8 of 24 games shown

Scarlet and Violet: 50 species

Species	Method	Level
Articuno	Level up	1
Suicune	Level up	1
Altaria	Level up	1
Abomasnow	Level up	1
Cresselia	Level up	6
Eiscue	Level up	6
Swablu	Level up	8
Lugia	Level up	9
Lotad	Level up	9
Lombre	Level up	9
Lapras	Level up	10
Snover	Level up	10
Wooper	Level up	12
Quagsire	Level up	12
Frosmoth	Level up	12
Chien-Pao	Level up	15
Cryogonal	Level up	16
Swinub	Level up	20
Piloswine	Level up	20
Mamoswine	Level up	20
Surskit	Level up	25
Glastrier	Level up	30
Wingull	Level up	35
Piplup	Level up	36
Pelipper	Level up	41
Prinplup	Level up	42
Finizen	Level up	44
Palafin	Level up	44
Empoleon	Level up	46
Volcanion	Level up	60
Mewtwo	Level up	64
Squirtle	Egg
Wartortle	Egg
Blastoise	Egg
Poliwag	Egg
Poliwhirl	Egg
Poliwrath	Egg
Dratini	Egg
Chinchou	Egg
Lanturn	Egg
Politoed	Egg
Ludicolo	Egg
Feebas	Egg
Milotic	Egg
Shellos	Egg
Alomomola	Egg
Bergmite	Egg
Sobble	Egg
Drizzile	Egg
Inteleon	Egg

Brilliant Diamond and Shining Pearl: 34 species

Species	Method	Level
Articuno	Level up	1
Suicune	Level up	1
Ludicolo	Level up	1
Masquerain	Level up	1
Altaria	Level up	1
Abomasnow	Level up	1
Cresselia	Level up	6
Swablu	Level up	8
Lugia	Level up	9
Lotad	Level up	9
Lombre	Level up	9
Lapras	Level up	10
Snover	Level up, Egg	10
Wooper	Level up	12
Quagsire	Level up	12
Wailmer	Level up	15
Wailord	Level up	15
Swinub	Level up	20
Piloswine	Level up	20
Mamoswine	Level up	20
Surskit	Level up	25
Wingull	Level up, Egg	35
Piplup	Level up	36
Pelipper	Level up	41
Prinplup	Level up	42
Empoleon	Level up	46
Mewtwo	Level up	64
Squirtle	Egg
Poliwag	Egg
Dratini	Egg
Chinchou	Egg
Corsola	Egg
Feebas	Egg
Shellos	Egg

Sword and Shield: 46 species

Species	Method	Level
Articuno	Level up	1
Suicune	Level up	1
Ludicolo	Level up	1
Altaria	Level up	1
Abomasnow	Level up	1
Vanillish	Level up	1
Vanilluxe	Level up	1
Cresselia	Level up	6
Eiscue	Level up	6
Swablu	Level up	8
Vanillite	Level up	8
Lugia	Level up	9
Lotad	Level up	9
Lombre	Level up	9
Lapras	Level up	10
Snover	Level up	10
Tapu Fini	Level up	10
Wooper	Level up	12
Quagsire	Level up	12
Frosmoth	Level up	12
Wailmer	Level up	15
Wailord	Level up	15
Swinub	Level up	20
Piloswine	Level up	20
Mamoswine	Level up	20
Cryogonal	Level up	20
Amaura	Level up	20
Aurorus	Level up	20
Glastrier	Level up	30
Wingull	Level up	35
Pelipper	Level up	41
Volcanion	Level up	60
Mewtwo	Level up	64
Squirtle	Egg
Poliwag	Egg
Dratini	Egg
Chinchou	Egg
Corsola	Egg
Feebas	Egg
Shellos	Egg
Tympole	Egg
Frillish	Egg
Bergmite	Egg
Wishiwashi	Egg
Drampa	Egg
Sobble	Egg

Let's Go Pikachu and Let's Go Eevee: 5 species

Species	Method	Level
Poliwrath	Level up	1
Dragonite	Level up	1
Articuno	Level up	8
Mewtwo	Level up	11
Lapras	Level up	13

Ultra Sun and Ultra Moon: 44 species

Species	Method	Level
Tapu Fini	Level up	1
Lapras	Level up	4
Articuno	Level up	8
Volcanion	Level up	8
Cryogonal	Level up	9
Wingull	Level up, Egg	12
Pelipper	Level up	12
Swablu	Level up	14
Altaria	Level up	14
Lotad	Level up	15
Vanillite	Level up	16
Vanillish	Level up	16
Vanilluxe	Level up	16
Amaura	Level up	18
Aurorus	Level up	18
Cresselia	Level up	20
Snover	Level up, Egg	21
Abomasnow	Level up	21
Wailmer	Level up	22
Wailord	Level up	22
Surskit	Level up	25
Swinub	Level up	35
Suicune	Level up	36
Piplup	Level up	36
Piloswine	Level up	37
Mamoswine	Level up	37
Prinplup	Level up	42
Wooper	Level up	43
Empoleon	Level up	46
Quagsire	Level up	48
Mewtwo	Level up	86
Squirtle	Egg
Poliwag	Egg
Dratini	Egg
Chinchou	Egg
Corsola	Egg
Feebas	Egg
Shellos	Egg
Tympole	Egg
Frillish	Egg
Alomomola	Egg
Bergmite	Egg
Wishiwashi	Egg
Drampa	Egg

Sun and Moon: 44 species

Species	Method	Level
Tapu Fini	Level up	1
Lapras	Level up	4
Articuno	Level up	8
Volcanion	Level up	8
Cryogonal	Level up	9
Wingull	Level up, Egg	12
Pelipper	Level up	12
Swablu	Level up	14
Altaria	Level up	14
Lotad	Level up	15
Vanillite	Level up	16
Vanillish	Level up	16
Vanilluxe	Level up	16
Amaura	Level up	18
Aurorus	Level up	18
Cresselia	Level up	20
Snover	Level up, Egg	21
Abomasnow	Level up	21
Wailmer	Level up	22
Wailord	Level up	22
Surskit	Level up	25
Swinub	Level up	35
Suicune	Level up	36
Piplup	Level up	36
Piloswine	Level up	37
Mamoswine	Level up	37
Prinplup	Level up	42
Wooper	Level up	43
Empoleon	Level up	46
Quagsire	Level up	48
Mewtwo	Level up	86
Squirtle	Egg
Poliwag	Egg
Dratini	Egg
Chinchou	Egg
Corsola	Egg
Feebas	Egg
Shellos	Egg
Tympole	Egg
Frillish	Egg
Alomomola	Egg
Bergmite	Egg
Wishiwashi	Egg
Drampa	Egg

Omega Ruby and Alpha Sapphire: 41 species

Species	Method	Level
Cryogonal	Level up	1, 21
Lapras	Level up	4
Articuno	Level up	8
Volcanion	Level up	8
Wingull	Level up, Egg	12
Pelipper	Level up	12
Swablu	Level up	14
Altaria	Level up	14
Lotad	Level up	15
Vanillite	Level up	16
Vanillish	Level up	16
Vanilluxe	Level up	16
Amaura	Level up	18
Aurorus	Level up	18
Cresselia	Level up	20
Snover	Level up, Egg	21
Abomasnow	Level up	21
Wailmer	Level up	22
Wailord	Level up	22
Surskit	Level up	25
Swinub	Level up	35
Suicune	Level up	36
Piplup	Level up	36
Piloswine	Level up	37
Mamoswine	Level up	37
Prinplup	Level up	42
Wooper	Level up	43
Empoleon	Level up	46
Quagsire	Level up	48
Mewtwo	Level up	86
Squirtle	Egg
Poliwag	Egg
Dratini	Egg
Chinchou	Egg
Corsola	Egg
Feebas	Egg
Shellos	Egg
Tympole	Egg
Frillish	Egg
Alomomola	Egg
Bergmite	Egg

X and Y: 41 species

Species	Method	Level
Cryogonal	Level up	1, 21
Lapras	Level up	4
Articuno	Level up	8
Volcanion	Level up	8
Lotad	Level up	11
Wingull	Level up, Egg	14
Pelipper	Level up	14
Swablu	Level up	15
Altaria	Level up	15
Vanillite	Level up	16
Vanillish	Level up	16
Vanilluxe	Level up	16
Amaura	Level up	18
Aurorus	Level up	18
Cresselia	Level up	20
Snover	Level up, Egg	21
Abomasnow	Level up	21
Wailmer	Level up	24
Wailord	Level up	24
Swinub	Level up	35
Suicune	Level up	36
Piplup	Level up	36
Piloswine	Level up	37
Surskit	Level up	37
Mamoswine	Level up	37
Prinplup	Level up	42
Wooper	Level up	43
Empoleon	Level up	46
Quagsire	Level up	48
Mewtwo	Level up	86
Squirtle	Egg
Poliwag	Egg
Dratini	Egg
Chinchou	Egg
Corsola	Egg
Feebas	Egg
Shellos	Egg
Tympole	Egg
Frillish	Egg
Alomomola	Egg
Bergmite	Egg