Roar is learned by 56 species by level, 232 by machine and 4 by egg

Effect, in PokéAPI's words

“Immediately ends wild battles. Forces trainers to switch Pokémon.”

Who learns it

234 species in all, 5 of 24 games shown

Scarlet and Violet: 171 species

Species	Method	Level
Walking Wake	Level up, Machine	Evolve
Arcanine	Level up, Machine	1
Iron Jugulis	Level up, Machine	7
Litten	Level up, Machine	9
Torracat	Level up, Machine	9
Incineroar	Level up, Machine	9
Greavard	Level up, Machine	9
Houndstone	Level up, Machine	9
Deino	Level up, Machine	12
Zweilous	Level up, Machine	12
Hydreigon	Level up, Machine	12
Houndour	Level up, Machine	13
Houndoom	Level up, Machine	13
Poochyena	Level up, Machine	16
Mightyena	Level up, Machine	16
Maschiff	Level up, Machine	18
Mabosstiff	Level up, Machine	18
Shinx	Level up, Machine	20
Raikou	Level up, Machine	24
Entei	Level up, Machine	24
Suicune	Level up, Machine	24
Luxio	Level up, Machine	24
Luxray	Level up, Machine	24
Snubbull	Level up, Machine	25
Fuecoco	Level up, Machine	25
Granbull	Level up, Machine	27
Rockruff	Level up, Machine	28
Crocalor	Level up, Machine	28
Skeledirge	Level up, Machine	28
Lycanroc	Level up, Machine	30
Fidough	Level up, Machine	30
Hippopotas	Level up, Machine	32
Hippowdon	Level up, Machine	32
Dachsbun	Level up, Machine	33
Tepig	Level up, Machine	39
Growlithe	Level up, Machine	44
Pignite	Level up, Machine	47
Emboar	Level up, Machine	55
Ivysaur	Machine
Venusaur	Machine
Charmander	Machine
Charmeleon	Machine
Charizard	Machine
Blastoise	Machine
Vulpix	Machine, Egg
Ninetales	Machine, Egg
Persian	Machine
Golem	Machine
Rhyhorn	Machine
Rhydon	Machine
Magmar	Machine
Gyarados	Machine
Eevee	Machine
Vaporeon	Machine
Jolteon	Machine
Flareon	Machine
Articuno	Machine
Moltres	Machine
Dragonite	Machine
Mew	Machine
Cyndaquil	Machine
Quilava	Machine
Typhlosion	Machine
Croconaw	Machine
Feraligatr	Machine
Flaaffy	Machine
Ampharos	Machine
Espeon	Machine
Umbreon	Machine
Swinub	Machine
Piloswine	Machine
Skarmory	Machine
Phanpy	Machine
Donphan	Machine
Stantler	Machine
Tyranitar	Machine
Sceptile	Machine
Blaziken	Machine
Mudkip	Machine
Marshtomp	Machine
Swampert	Machine
Vigoroth	Machine
Slaking	Machine
Numel	Machine
Camerupt	Machine
Altaria	Machine
Zangoose	Machine
Tropius	Machine
Bagon	Machine
Shelgon	Machine
Salamence	Machine
Latias	Machine
Latios	Machine
Kyogre	Machine
Groudon	Machine
Rayquaza	Machine
Turtwig	Machine
Grotle	Machine
Torterra	Machine
Infernape	Machine
Empoleon	Machine
Cranidos	Machine
Rampardos	Machine
Shieldon	Machine
Bastiodon	Machine
Buizel	Machine
Floatzel	Machine
Stunky	Machine
Skuntank	Machine
Lucario	Machine
Rhyperior	Machine
Magmortar	Machine
Leafeon	Machine
Glaceon	Machine
Mamoswine	Machine
Dialga	Machine
Palkia	Machine
Giratina	Machine
Arceus	Machine
Zebstrika	Machine
Sandile	Machine
Krokorok	Machine
Krookodile	Machine
Scraggy	Machine
Scrafty	Machine
Zorua	Machine
Zoroark	Machine
Axew	Machine
Fraxure	Machine
Haxorus	Machine
Beartic	Machine
Cobalion	Machine
Terrakion	Machine
Virizion	Machine
Reshiram	Machine
Zekrom	Machine
Kyurem	Machine
Keldeo	Machine
Chespin	Machine
Quilladin	Machine
Chesnaught	Machine
Litleo	Machine
Pyroar	Machine
Skiddo	Machine
Gogoat	Machine
Sylveon	Machine
Volcanion	Machine
Gumshoos	Machine
Mudbray	Machine, Egg
Mudsdale	Machine
Jangmo-o	Machine
Hakamo-o	Machine
Kommo-o	Machine
Solgaleo	Machine
Duraludon	Machine
Zamazenta	Machine
Urshifu	Machine
Zarude	Machine
Glastrier	Machine
Wyrdeer	Machine
Ursaluna	Machine
Farigiraf	Machine
Great Tusk	Machine
Scream Tail	Machine
Roaring Moon	Machine
Koraidon	Machine
Okidogi	Machine
Archaludon	Machine
Gouging Fire	Machine
Raging Bolt	Machine
Terapagos	Machine

Brilliant Diamond and Shining Pearl: 113 species

Species	Method	Level
Arcanine	Level up, Machine	1
Aron	Level up, Machine	12
Lairon	Level up, Machine	12
Aggron	Level up, Machine	12
Houndour	Level up, Machine	13
Houndoom	Level up, Machine	13
Poochyena	Level up, Machine	16
Mightyena	Level up, Machine	16
Shinx	Level up, Machine	20
Raikou	Level up, Machine	24
Entei	Level up, Machine	24
Suicune	Level up, Machine	24
Luxio	Level up, Machine	24
Luxray	Level up, Machine	24
Aerodactyl	Level up, Machine	25
Snubbull	Level up, Machine	25
Whismur	Level up, Machine	25
Granbull	Level up, Machine	27
Electrike	Level up, Machine	28
Loudred	Level up, Machine	29
Exploud	Level up, Machine	29
Manectric	Level up, Machine	30
Hippopotas	Level up, Machine	32
Hippowdon	Level up, Machine	32
Growlithe	Level up, Machine	44
Venusaur	Machine
Charizard	Machine
Blastoise	Machine
Raticate	Machine
Nidoqueen	Machine
Nidoking	Machine
Vulpix	Machine
Ninetales	Machine
Persian	Machine
Golem	Machine
Onix	Machine
Rhyhorn	Machine
Rhydon	Machine
Kangaskhan	Machine
Gyarados	Machine
Lapras	Machine
Vaporeon	Machine
Jolteon	Machine
Flareon	Machine
Articuno	Machine
Zapdos	Machine
Moltres	Machine
Dragonite	Machine
Mew	Machine
Quilava	Machine
Typhlosion	Machine
Croconaw	Machine
Feraligatr	Machine
Steelix	Machine
Teddiursa	Machine
Ursaring	Machine
Swinub	Machine
Piloswine	Machine
Skarmory	Machine
Phanpy	Machine
Donphan	Machine
Stantler	Machine
Tyranitar	Machine
Lugia	Machine
Ho-Oh	Machine
Sceptile	Machine
Blaziken	Machine
Swampert	Machine
Linoone	Machine
Vigoroth	Machine
Slaking	Machine
Sharpedo	Machine
Wailmer	Machine
Wailord	Machine
Camerupt	Machine
Altaria	Machine
Zangoose	Machine
Tropius	Machine
Sealeo	Machine
Walrein	Machine
Bagon	Machine
Shelgon	Machine
Salamence	Machine
Latias	Machine
Latios	Machine
Kyogre	Machine
Groudon	Machine
Rayquaza	Machine
Torterra	Machine
Infernape	Machine
Empoleon	Machine
Cranidos	Machine
Rampardos	Machine
Shieldon	Machine
Bastiodon	Machine
Floatzel	Machine
Purugly	Machine
Stunky	Machine
Skuntank	Machine
Gible	Machine
Gabite	Machine
Garchomp	Machine
Riolu	Machine
Lucario	Machine
Drapion	Machine
Rhyperior	Machine
Leafeon	Machine
Glaceon	Machine
Mamoswine	Machine
Dialga	Machine
Palkia	Machine
Heatran	Machine
Giratina	Machine

Sword and Shield: 36 species

Species	Method	Level
Arcanine	Level up	1
Tyrantrum	Level up	1
Tyrunt	Level up	4
Litten	Level up	9
Torracat	Level up	9
Incineroar	Level up	9
Aron	Level up	12
Lairon	Level up	12
Aggron	Level up	12
Deino	Level up	12
Zweilous	Level up	12
Hydreigon	Level up	12
Yamper	Level up	15
Boltund	Level up	15
Shinx	Level up	20
Raikou	Level up	24
Entei	Level up	24
Suicune	Level up	24
Luxio	Level up	24
Luxray	Level up	24
Aerodactyl	Level up	25
Whismur	Level up	25
Electrike	Level up	28
Rockruff	Level up	28
Loudred	Level up	29
Exploud	Level up	29
Manectric	Level up	30
Lycanroc	Level up	30
Hippopotas	Level up	32
Hippowdon	Level up	32
Lillipup	Level up	40
Growlithe	Level up	44
Herdier	Level up	54
Stoutland	Level up	62
Vulpix	Egg
Mudbray	Egg

Let's Go Pikachu and Let's Go Eevee: 4 species

Species	Method	Level
Growlithe	Level up	1
Arcanine	Level up	1
Aerodactyl	Level up	7
Vulpix	Level up	28

Ultra Sun and Ultra Moon: 182 species

Species	Method	Level
Growlithe	Level up, Machine	1
Arcanine	Level up, Machine	1
Tyrantrum	Level up, Machine	1, 6
Tyrunt	Level up, Machine	6
Vulpix	Level up, Machine	7
Aerodactyl	Level up, Machine	9
Houndour	Level up, Machine	13
Houndoom	Level up, Machine	13
Raikou	Level up, Machine	15
Entei	Level up, Machine	15
Poochyena	Level up, Machine	16
Mightyena	Level up, Machine	16
Litten	Level up, Machine	18
Aron	Level up, Machine	19
Lairon	Level up, Machine	19
Aggron	Level up, Machine	19
Torracat	Level up, Machine	19
Incineroar	Level up, Machine	19
Deino	Level up, Machine	20
Zweilous	Level up, Machine	20
Hydreigon	Level up, Machine	20
Shinx	Level up, Machine	21
Luxio	Level up, Machine	23
Luxray	Level up, Machine	23
Snubbull	Level up, Machine	25
Lillipup	Level up, Machine	26
Rockruff	Level up, Machine	26
Lycanroc	Level up, Machine	26
Granbull	Level up, Machine	27
Whismur	Level up, Machine	29
Herdier	Level up, Machine	29
Stoutland	Level up, Machine	29
Loudred	Level up, Machine	32
Exploud	Level up, Machine	32
Electrike	Level up, Machine	34
Manectric	Level up, Machine	36
Tepig	Level up, Machine	39
Pignite	Level up, Machine	47
Emboar	Level up, Machine	55
Venusaur	Machine
Charizard	Machine
Blastoise	Machine
Raticate	Machine
Nidoqueen	Machine
Nidoking	Machine
Ninetales	Machine
Persian	Machine
Golem	Machine
Onix	Machine
Rhyhorn	Machine
Rhydon	Machine
Kangaskhan	Machine
Gyarados	Machine
Lapras	Machine
Vaporeon	Machine
Jolteon	Machine
Flareon	Machine
Articuno	Machine
Zapdos	Machine
Moltres	Machine
Dragonite	Machine
Mew	Machine
Quilava	Machine
Typhlosion	Machine
Croconaw	Machine
Feraligatr	Machine
Steelix	Machine
Teddiursa	Machine
Ursaring	Machine
Swinub	Machine
Piloswine	Machine
Skarmory	Machine
Phanpy	Machine
Donphan	Machine
Stantler	Machine
Suicune	Machine
Tyranitar	Machine
Lugia	Machine
Ho-Oh	Machine
Sceptile	Machine
Blaziken	Machine
Swampert	Machine
Linoone	Machine
Vigoroth	Machine
Slaking	Machine
Sharpedo	Machine
Wailmer	Machine
Wailord	Machine
Camerupt	Machine
Altaria	Machine
Zangoose	Machine
Tropius	Machine
Sealeo	Machine
Walrein	Machine
Bagon	Machine
Shelgon	Machine
Salamence	Machine
Latias	Machine
Latios	Machine
Kyogre	Machine
Groudon	Machine
Rayquaza	Machine
Torterra	Machine
Infernape	Machine
Empoleon	Machine
Cranidos	Machine
Rampardos	Machine
Shieldon	Machine
Bastiodon	Machine
Floatzel	Machine
Purugly	Machine
Stunky	Machine
Skuntank	Machine
Gible	Machine
Gabite	Machine
Garchomp	Machine
Riolu	Machine
Lucario	Machine
Hippopotas	Machine
Hippowdon	Machine
Drapion	Machine
Rhyperior	Machine
Leafeon	Machine
Glaceon	Machine
Mamoswine	Machine
Dialga	Machine
Palkia	Machine
Heatran	Machine
Giratina	Machine
Arceus	Machine
Sandile	Machine
Krokorok	Machine
Krookodile	Machine
Darumaka	Machine
Darmanitan	Machine
Scraggy	Machine
Scrafty	Machine
Archen	Machine
Archeops	Machine
Zorua	Machine
Zoroark	Machine
Eelektross	Machine
Axew	Machine
Fraxure	Machine
Haxorus	Machine
Beartic	Machine
Druddigon	Machine
Cobalion	Machine
Terrakion	Machine
Virizion	Machine
Keldeo	Machine
Chespin	Machine
Quilladin	Machine
Chesnaught	Machine
Litleo	Machine
Pyroar	Machine
Skiddo	Machine
Gogoat	Machine
Pancham	Machine
Pangoro	Machine
Furfrou	Machine
Amaura	Machine
Aurorus	Machine
Avalugg	Machine
Xerneas	Machine
Volcanion	Machine
Gumshoos	Machine
Mudbray	Machine
Mudsdale	Machine
Stufful	Machine
Bewear	Machine
Type: Null	Machine
Silvally	Machine
Turtonator	Machine
Drampa	Machine
Jangmo-o	Machine
Hakamo-o	Machine
Kommo-o	Machine
Tapu Koko	Machine
Tapu Bulu	Machine
Solgaleo	Machine
Lunala	Machine

Changed over time

One change since Generation I

1. Through Gen VAccuracy 100%Removed from X and Y, Generation VI