Leaf Storm is learned by 32 species by level, 100 by machine and 10 by egg

Effect, in PokéAPI's words

“Lowers the user’s Special Attack by two stages after inflicting damage.”

Who learns it

102 species in all, 8 of 13 games shown

Scarlet and Violet: 91 species

Species	Method	Level
Victreebel	Level up, Machine	Evolve
Exeggutor	Level up, Machine	1
Tropius	Level up, Machine	1
Lilligant	Level up, Machine	1
Decidueye	Level up, Machine	1
Treecko	Level up, Machine	39
Snivy	Level up, Machine	40
Petilil	Level up, Machine	42
Sunflora	Level up, Machine	43
Turtwig	Level up, Machine	45
Steenee	Level up, Machine	46
Tsareena	Level up, Machine	46
Floragato	Level up, Machine	46
Servine	Level up, Machine	48
Leavanny	Level up, Machine	50
Grotle	Level up, Machine	52
Grovyle	Level up, Machine	55
Sceptile	Level up, Machine	56
Serperior	Level up, Machine	56
Torterra	Level up, Machine	57
Poltchageist	Level up, Machine	60
Sinistcha	Level up, Machine	60
Meowscarada	Level up, Machine	64
Wo-Chien	Level up, Machine	75
Bulbasaur	Machine
Ivysaur	Machine
Venusaur	Machine
Oddish	Machine
Gloom	Machine
Vileplume	Machine
Bellsprout	Machine
Weepinbell	Machine
Exeggcute	Machine
Mew	Machine
Chikorita	Machine
Bayleef	Machine
Meganium	Machine
Bellossom	Machine
Hoppip	Machine
Skiploom	Machine
Jumpluff	Machine
Sunkern	Machine
Ludicolo	Machine
Seedot	Machine
Nuzleaf	Machine
Shiftry	Machine
Breloom	Machine
Cacnea	Machine
Cacturne	Machine
Snover	Machine
Abomasnow	Machine
Leafeon	Machine
Shaymin	Machine
Deerling	Machine
Sawsbuck	Machine
Foongus	Machine
Amoonguss	Machine
Virizion	Machine
Chespin	Machine
Quilladin	Machine
Chesnaught	Machine
Skiddo	Machine
Gogoat	Machine
Trevenant	Machine
Rowlet	Machine
Dartrix	Machine
Fomantis	Machine
Lurantis	Machine
Bounsweet	Machine
Grookey	Machine
Thwackey	Machine
Rillaboom	Machine
Flapple	Machine
Appletun	Machine
Zarude	Machine
Calyrex	Machine
Sprigatito	Machine
Smoliv	Machine
Dolliv	Machine
Arboliva	Machine
Bramblin	Machine
Brambleghast	Machine
Toedscool	Machine
Toedscruel	Machine
Capsakid	Machine
Scovillain	Machine
Brute Bonnet	Machine
Iron Leaves	Machine
Dipplin	Machine
Ogerpon	Machine
Hydrapple	Machine

Legends Arceus: 3 species

Species	Method	Level
Rowlet	Level up	43
Dartrix	Level up	43
Petilil	Level up	47

Brilliant Diamond and Shining Pearl: 18 species

Species	Method	Level
Exeggutor	Level up	1
Tropius	Level up, Egg	1, 61
Victreebel	Level up	32
Treecko	Level up, Egg	39
Sunflora	Level up	43
Turtwig	Level up	45
Wormadam	Level up	47
Grotle	Level up	52
Grovyle	Level up	55
Torterra	Level up	57
Sceptile	Level up	63
Celebi	Level up	90
Bulbasaur	Egg
Exeggcute	Egg
Tangela	Egg
Chikorita	Egg
Roselia	Egg
Budew	Egg

Sword and Shield: 34 species

Species	Method	Level
Exeggutor	Level up, Machine	1
Lilligant	Level up, Machine	1
Decidueye	Level up, Machine	1
Gossifleur	Level up, Machine	36
Treecko	Level up, Machine	39
Petilil	Level up, Machine	42
Eldegoss	Level up, Machine	46
Steenee	Level up, Machine	52
Tsareena	Level up, Machine	52
Grovyle	Level up, Machine	55
Sceptile	Level up, Machine	63
Celebi	Level up, Machine	90
Bulbasaur	Machine
Ivysaur	Machine
Venusaur	Machine
Exeggcute	Machine
Tangela	Machine
Mew	Machine
Bellossom	Machine
Ludicolo	Machine
Shiftry	Machine
Roselia	Machine
Budew	Machine
Roserade	Machine
Abomasnow	Machine
Tangrowth	Machine
Leafeon	Machine
Maractus	Machine
Virizion	Machine
Trevenant	Machine
Fomantis	Machine
Lurantis	Machine
Rillaboom	Machine
Calyrex	Machine

Ultra Sun and Ultra Moon: 30 species

Species	Method	Level
Bellossom	Level up	1, 69
Sceptile	Level up	1, 63
Tropius	Level up, Egg	1, 61
Decidueye	Level up	1
Victreebel	Level up	32
Sunflora	Level up	43
Snivy	Level up	43
Shiftry	Level up	44
Turtwig	Level up	45
Steenee	Level up	45
Tsareena	Level up	45
Petilil	Level up	46
Exeggutor	Level up	47
Wormadam	Level up	47
Leavanny	Level up	50
Grotle	Level up	52
Servine	Level up	52
Torterra	Level up	57
Grovyle	Level up	58
Serperior	Level up	62
Celebi	Level up	82
Bulbasaur	Egg
Exeggcute	Egg
Tangela	Egg
Chikorita	Egg
Treecko	Egg
Roselia	Egg
Budew	Egg
Pansage	Egg
Fomantis	Egg

Sun and Moon: 29 species

Species	Method	Level
Bellossom	Level up	1, 69
Sceptile	Level up	1, 63
Tropius	Level up, Egg	1, 61
Victreebel	Level up	32
Sunflora	Level up	43
Snivy	Level up	43
Shiftry	Level up	44
Turtwig	Level up	45
Steenee	Level up	45
Tsareena	Level up	45
Petilil	Level up	46
Exeggutor	Level up	47
Wormadam	Level up	47
Leavanny	Level up	50
Grotle	Level up	52
Servine	Level up	52
Torterra	Level up	57
Grovyle	Level up	58
Serperior	Level up	62
Celebi	Level up	82
Bulbasaur	Egg
Exeggcute	Egg
Tangela	Egg
Chikorita	Egg
Treecko	Egg
Roselia	Egg
Budew	Egg
Pansage	Egg
Fomantis	Egg

Omega Ruby and Alpha Sapphire: 26 species

Species	Method	Level
Bellossom	Level up	1, 64
Sceptile	Level up	1, 63
Tropius	Level up, Egg	1, 61
Sunflora	Level up	43
Snivy	Level up	43
Shiftry	Level up	44
Turtwig	Level up	45
Petilil	Level up	46
Victreebel	Level up	47
Exeggutor	Level up	47
Wormadam	Level up	47
Leavanny	Level up	50
Grotle	Level up	52
Servine	Level up	52
Torterra	Level up	57
Grovyle	Level up	58
Serperior	Level up	62
Celebi	Level up	82
Bulbasaur	Egg
Exeggcute	Egg
Tangela	Egg
Chikorita	Egg
Treecko	Egg
Roselia	Egg
Budew	Egg
Pansage	Egg

X and Y: 26 species

Species	Method	Level
Bellossom	Level up	1, 53
Sceptile	Level up	1, 67
Tropius	Level up, Egg	1, 71
Sunflora	Level up	43
Snivy	Level up	43
Turtwig	Level up	45
Petilil	Level up	46
Victreebel	Level up	47
Exeggutor	Level up	47
Wormadam	Level up	47
Shiftry	Level up	49
Leavanny	Level up	50
Grotle	Level up	52
Servine	Level up	52
Torterra	Level up	57
Grovyle	Level up	59
Serperior	Level up	62
Celebi	Level up	82
Bulbasaur	Egg
Exeggcute	Egg
Tangela	Egg
Chikorita	Egg
Treecko	Egg
Roselia	Egg
Budew	Egg
Pansage	Egg

Changed over time

One change since Generation IV

1. Through Gen VPower 140130 from X and Y, Generation VI