Me First is learned by 17 species by level and 17 by egg

Effect, in PokéAPI's words

“Uses the target’s move against it before it attacks, with power increased by half.”

Who learns it

32 species in all, 8 of 9 games shown

Ultra Sun and Ultra Moon: 32 species

Species	Method	Level
Golduck	Level up	1
Stantler	Level up, Egg	1, 55
Accelgor	Level up	28
Lucario	Level up	37
Lickitung	Level up	41
Absol	Level up, Egg	41
Lickilicky	Level up	41
Fletchling	Level up	41
Sentret	Level up	42
Fletchinder	Level up	46
Talonflame	Level up	49
Furret	Level up	50
Natu	Level up	50
Xatu	Level up	57
Pheromosa	Level up	59
Mew	Level up	70
Mewtwo	Level up	93
Rattata	Egg
Slowpoke	Egg
Pinsir	Egg
Misdreavus	Egg
Poochyena	Egg
Buizel	Egg
Croagunk	Egg
Blitzle	Egg
Sewaddle	Egg
Sandile	Egg
Ducklett	Egg
Stunfisk	Egg
Mienfoo	Egg
Pancham	Egg
Hawlucha	Egg

Sun and Moon: 32 species

Species	Method	Level
Golduck	Level up	1
Stantler	Level up, Egg	1, 55
Accelgor	Level up	28
Lucario	Level up	37
Lickitung	Level up	41
Absol	Level up, Egg	41
Lickilicky	Level up	41
Fletchling	Level up	41
Sentret	Level up	42
Fletchinder	Level up	46
Talonflame	Level up	49
Furret	Level up	50
Natu	Level up	50
Xatu	Level up	57
Pheromosa	Level up	59
Mew	Level up	70
Mewtwo	Level up	93
Rattata	Egg
Slowpoke	Egg
Pinsir	Egg
Misdreavus	Egg
Poochyena	Egg
Buizel	Egg
Croagunk	Egg
Blitzle	Egg
Sewaddle	Egg
Sandile	Egg
Ducklett	Egg
Stunfisk	Egg
Mienfoo	Egg
Pancham	Egg
Hawlucha	Egg

Omega Ruby and Alpha Sapphire: 30 species

Species	Method	Level
Stantler	Level up, Egg	1, 55
Accelgor	Level up	28
Lucario	Level up	37
Lickitung	Level up	41
Absol	Level up, Egg	41
Lickilicky	Level up	41
Fletchling	Level up	41
Sentret	Level up	42
Fletchinder	Level up	46
Talonflame	Level up	49
Furret	Level up	50
Natu	Level up	50
Xatu	Level up	57
Mew	Level up	70
Mewtwo	Level up	93
Rattata	Egg
Slowpoke	Egg
Pinsir	Egg
Misdreavus	Egg
Poochyena	Egg
Buizel	Egg
Croagunk	Egg
Blitzle	Egg
Sewaddle	Egg
Sandile	Egg
Ducklett	Egg
Stunfisk	Egg
Mienfoo	Egg
Pancham	Egg
Hawlucha	Egg

X and Y: 30 species

Species	Method	Level
Stantler	Level up, Egg	1, 55
Absol	Level up, Egg	1, 60
Natu	Level up	20
Xatu	Level up	20
Accelgor	Level up	28
Lucario	Level up	37
Lickitung	Level up	41
Lickilicky	Level up	41
Fletchling	Level up	41
Sentret	Level up	42
Fletchinder	Level up	46
Talonflame	Level up	49
Furret	Level up	50
Mew	Level up	70
Mewtwo	Level up	93
Rattata	Egg
Slowpoke	Egg
Pinsir	Egg
Misdreavus	Egg
Poochyena	Egg
Buizel	Egg
Croagunk	Egg
Blitzle	Egg
Sewaddle	Egg
Sandile	Egg
Ducklett	Egg
Stunfisk	Egg
Mienfoo	Egg
Pancham	Egg
Hawlucha	Egg

Black 2 and White 2: 22 species

Species	Method	Level
Lucario	Level up	19
Natu	Level up	20
Xatu	Level up	20
Accelgor	Level up	28
Lickitung	Level up	41
Lickilicky	Level up	41
Sentret	Level up	42
Furret	Level up	50
Stantler	Level up, Egg	55
Absol	Level up, Egg	60
Mew	Level up	70
Mewtwo	Level up	71
Rattata	Egg
Slowpoke	Egg
Pinsir	Egg
Poochyena	Egg
Buizel	Egg
Croagunk	Egg
Blitzle	Egg
Sewaddle	Egg
Ducklett	Egg
Mienfoo	Egg

Black and White: 22 species

Species	Method	Level
Natu	Level up	20
Xatu	Level up	20
Accelgor	Level up	28
Lucario	Level up	29
Lickitung	Level up	41
Lickilicky	Level up	41
Sentret	Level up	42
Furret	Level up	50
Stantler	Level up, Egg	55
Absol	Level up, Egg	57
Mew	Level up	70
Mewtwo	Level up	71
Rattata	Egg
Slowpoke	Egg
Pinsir	Egg
Poochyena	Egg
Buizel	Egg
Croagunk	Egg
Blitzle	Egg
Sewaddle	Egg
Ducklett	Egg
Mienfoo	Egg

HeartGold and SoulSilver: 15 species

Species	Method	Level
Natu	Level up	20
Xatu	Level up	20
Lucario	Level up	29
Lickitung	Level up	37
Lickilicky	Level up	37
Sentret	Level up	42
Furret	Level up	50
Stantler	Level up	53
Absol	Level up, Egg	57
Mew	Level up	70
Mewtwo	Level up	79
Rattata	Egg
Slowpoke	Egg
Poochyena	Egg
Croagunk	Egg

Platinum: 15 species

Species	Method	Level
Natu	Level up	20
Xatu	Level up	20
Lucario	Level up	29
Lickitung	Level up	37
Lickilicky	Level up	37
Sentret	Level up	42
Furret	Level up	50
Stantler	Level up	53
Absol	Level up, Egg	57
Mew	Level up	70
Mewtwo	Level up	79
Rattata	Egg
Slowpoke	Egg
Poochyena	Egg
Croagunk	Egg

Changed over time

One change since Generation IV

1. Through Gen IVPower 0Removed from Black and White, Generation V