Lock-On is learned by 21 species by level and 2 by egg

Effect, in PokéAPI's words

“Ensures that the user’s next move will hit the target.”

Who learns it

23 species in all, 8 of 19 games shown

Scarlet and Violet: 15 species

Species	Method	Level
Drakloak	Level up	6
Dragapult	Level up	6
Magearna	Level up	42
Nosepass	Level up	43
Probopass	Level up	43
Magnemite	Level up	48
Porygon2	Level up	50
Porygon	Level up	55
Porygon-Z	Level up	55
Magneton	Level up	58
Magnezone	Level up	58
Regirock	Level up	60
Regice	Level up	60
Registeel	Level up	60
Regieleki	Level up	60

Brilliant Diamond and Shining Pearl: 13 species

Species	Method	Level
Remoraid	Level up	24
Octillery	Level up	24
Nosepass	Level up	43
Probopass	Level up	43
Magnemite	Level up	48
Porygon	Level up	55
Porygon2	Level up	55
Porygon-Z	Level up	55
Magneton	Level up	58
Magnezone	Level up	58
Regirock	Level up	60
Regice	Level up	60
Registeel	Level up	60

Sword and Shield: 18 species

Species	Method	Level
Drakloak	Level up	6
Dragapult	Level up	6
Remoraid	Level up	24
Octillery	Level up	24
Klink	Level up	36
Klang	Level up	36
Klinklang	Level up	36
Magnemite	Level up	48
Porygon	Level up	55
Porygon2	Level up	55
Porygon-Z	Level up	55
Magneton	Level up	58
Magnezone	Level up	58
Regirock	Level up	60
Regice	Level up	60
Registeel	Level up	60
Regieleki	Level up	60
Genesect	Level up	77

Ultra Sun and Ultra Moon: 18 species

Species	Method	Level
Remoraid	Level up	6
Genesect	Level up	11
Magnemite	Level up	41
Nosepass	Level up	43
Probopass	Level up	43
Porygon	Level up	45
Porygon2	Level up	45
Porygon-Z	Level up	45
Magneton	Level up	49
Magnezone	Level up	49
Klink	Level up	50
Regirock	Level up	55
Regice	Level up	55
Registeel	Level up	55
Klang	Level up	56
Klinklang	Level up	60
Roggenrola	Egg
Klefki	Egg

Sun and Moon: 18 species

Species	Method	Level
Remoraid	Level up	6
Genesect	Level up	11
Magnemite	Level up	41
Nosepass	Level up	43
Probopass	Level up	43
Porygon	Level up	45
Porygon2	Level up	45
Porygon-Z	Level up	45
Magneton	Level up	49
Magnezone	Level up	49
Klink	Level up	50
Regirock	Level up	55
Regice	Level up	55
Registeel	Level up	55
Klang	Level up	56
Klinklang	Level up	60
Roggenrola	Egg
Klefki	Egg

Omega Ruby and Alpha Sapphire: 18 species

Species	Method	Level
Remoraid	Level up	6
Genesect	Level up	11
Magnemite	Level up	41
Nosepass	Level up	43
Probopass	Level up	43
Porygon	Level up	45
Porygon2	Level up	45
Porygon-Z	Level up	45
Magneton	Level up	49
Magnezone	Level up	49
Klink	Level up	50
Regirock	Level up	55
Regice	Level up	55
Registeel	Level up	55
Klang	Level up	56
Klinklang	Level up	60
Roggenrola	Egg
Klefki	Egg

X and Y: 18 species

Species	Method	Level
Regirock	Level up	1, 57
Regice	Level up	1, 57
Registeel	Level up	1, 57
Remoraid	Level up	6
Genesect	Level up	11
Porygon	Level up	45
Porygon2	Level up	45
Porygon-Z	Level up	45
Magnemite	Level up	46
Nosepass	Level up	50
Probopass	Level up	50
Klink	Level up	50
Magneton	Level up	56
Magnezone	Level up	56
Klang	Level up	56
Klinklang	Level up	60
Roggenrola	Egg
Klefki	Egg

Black 2 and White 2: 17 species

Species	Method	Level
Remoraid	Level up	6
Genesect	Level up	11
Porygon	Level up	45
Porygon2	Level up	45
Porygon-Z	Level up	45
Magnemite	Level up	46
Nosepass	Level up	50
Probopass	Level up	50
Klink	Level up	51
Magneton	Level up	56
Magnezone	Level up	56
Klang	Level up	56
Regirock	Level up	57
Regice	Level up	57
Registeel	Level up	57
Klinklang	Level up	60
Roggenrola	Egg