Psyshock is learned by 26 species by level and 131 by machine

Effect, in PokéAPI's words

“Inflicts damage based on the target’s Defense, not Special Defense.”

Who learns it

131 species in all, 7 of 9 games shown

Scarlet and Violet: 97 species

Species	Method	Level
Armarouge	Level up, Machine	Evolve
Exeggutor	Level up, Machine	1
Gothita	Level up, Machine	20
Gothorita	Level up, Machine	20
Gothitelle	Level up, Machine	20
Solosis	Level up, Machine	20
Duosion	Level up, Machine	20
Reuniclus	Level up, Machine	20
Calyrex	Level up, Machine	24
Deoxys	Level up, Machine	25
Bruxish	Level up, Machine	25
Iron Crown	Level up, Machine	28
Fennekin	Level up, Machine	31
Espurr	Level up, Machine	33
Braixen	Level up, Machine	36
Spoink	Level up, Machine	38
Delphox	Level up, Machine	38
Meowstic	Level up, Machine	39
Grumpig	Level up, Machine	42
Drowzee	Level up, Machine	45
Hypno	Level up, Machine	51
Flutter Mane	Level up, Machine	63
Clefairy	Machine
Clefable	Machine
Ninetales	Machine
Jigglypuff	Machine
Wigglytuff	Machine
Psyduck	Machine
Golduck	Machine
Slowpoke	Machine
Slowbro	Machine
Exeggcute	Machine
Porygon	Machine
Mewtwo	Machine
Mew	Machine
Cleffa	Machine
Espeon	Machine
Slowking	Machine
Misdreavus	Machine
Girafarig	Machine
Porygon2	Machine
Stantler	Machine
Lugia	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Meditite	Machine
Medicham	Machine
Chimecho	Machine
Metang	Machine
Metagross	Machine
Latias	Machine
Latios	Machine
Jirachi	Machine
Mismagius	Machine
Chingling	Machine
Bronzor	Machine
Bronzong	Machine
Spiritomb	Machine
Porygon-Z	Machine
Gallade	Machine
Uxie	Machine
Mesprit	Machine
Azelf	Machine
Cresselia	Machine
Darkrai	Machine
Arceus	Machine
Meloetta	Machine
Inkay	Machine
Malamar	Machine
Sylveon	Machine
Klefki	Machine
Diancie	Machine
Hoopa	Machine
Oranguru	Machine
Solgaleo	Machine
Lunala	Machine
Necrozma	Machine
Magearna	Machine
Sinistea	Machine
Polteageist	Machine
Hatenna	Machine
Hattrem	Machine
Hatterene	Machine
Alcremie	Machine
Indeedee	Machine
Wyrdeer	Machine
Rabsca	Machine
Flittle	Machine
Espathra	Machine
Farigiraf	Machine
Great Tusk	Machine
Scream Tail	Machine
Gholdengo	Machine
Iron Valiant	Machine
Munkidori	Machine
Iron Boulder	Machine

Brilliant Diamond and Shining Pearl: 8 species

Species	Method	Level
Exeggutor	Level up	1
Lunatone	Level up	20
Kadabra	Level up	30
Alakazam	Level up	30
Spoink	Level up	38
Grumpig	Level up	42
Drowzee	Level up	57
Hypno	Level up	57

Sword and Shield: 90 species

Species	Method	Level
Exeggutor	Level up, Machine	1
Lunatone	Level up, Machine	20
Gothita	Level up, Machine	20
Gothorita	Level up, Machine	20
Gothitelle	Level up, Machine	20
Solosis	Level up, Machine	20
Duosion	Level up, Machine	20
Reuniclus	Level up, Machine	20
Calyrex	Level up, Machine	24
Kadabra	Level up, Machine	30
Alakazam	Level up, Machine	30
Espurr	Level up, Machine	33
Meowstic	Level up, Machine	39
Tapu Lele	Level up, Machine	45
Clefairy	Machine
Clefable	Machine
Ninetales	Machine
Psyduck	Machine
Golduck	Machine
Abra	Machine
Slowpoke	Machine
Slowbro	Machine
Starmie	Machine
Mr. Mime	Machine
Jynx	Machine
Porygon	Machine
Mewtwo	Machine
Mew	Machine
Cleffa	Machine
Togepi	Machine
Togetic	Machine
Natu	Machine
Xatu	Machine
Espeon	Machine
Slowking	Machine
Porygon2	Machine
Smoochum	Machine
Lugia	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Solrock	Machine
Baltoy	Machine
Claydol	Machine
Metang	Machine
Metagross	Machine
Latias	Machine
Latios	Machine
Jirachi	Machine
Bronzor	Machine
Bronzong	Machine
Mime Jr.	Machine
Togekiss	Machine
Porygon-Z	Machine
Gallade	Machine
Uxie	Machine
Mesprit	Machine
Azelf	Machine
Cresselia	Machine
Victini	Machine
Munna	Machine
Musharna	Machine
Woobat	Machine
Swoobat	Machine
Audino	Machine
Sigilyph	Machine
Elgyem	Machine
Beheeyem	Machine
Aromatisse	Machine
Malamar	Machine
Sylveon	Machine
Klefki	Machine
Xerneas	Machine
Diancie	Machine
Oranguru	Machine
Solgaleo	Machine
Lunala	Machine
Nihilego	Machine
Necrozma	Machine
Blacephalon	Machine
Dottler	Machine
Orbeetle	Machine
Sinistea	Machine
Polteageist	Machine
Hatenna	Machine
Hattrem	Machine
Hatterene	Machine
Mr. Rime	Machine
Alcremie	Machine
Indeedee	Machine

Ultra Sun and Ultra Moon: 96 species

Species	Method	Level
Lunatone	Level up, Machine	1
Exeggutor	Level up, Machine	17
Gothita	Level up, Machine	25
Gothorita	Level up, Machine	25
Gothitelle	Level up, Machine	25
Solosis	Level up, Machine	25
Duosion	Level up, Machine	25
Reuniclus	Level up, Machine	25
Espurr	Level up, Machine	25
Meowstic	Level up, Machine	25
Fennekin	Level up, Machine	31
Tapu Lele	Level up, Machine	32
Braixen	Level up, Machine	36
Spoink	Level up, Machine	38
Delphox	Level up, Machine	38
Grumpig	Level up, Machine	42
Drowzee	Level up, Machine	57
Hypno	Level up, Machine	57
Clefairy	Machine
Clefable	Machine
Ninetales	Machine
Psyduck	Machine
Golduck	Machine
Abra	Machine
Kadabra	Machine
Alakazam	Machine
Slowpoke	Machine
Slowbro	Machine
Starmie	Machine
Mr. Mime	Machine
Jynx	Machine
Porygon	Machine
Mewtwo	Machine
Mew	Machine
Cleffa	Machine
Togepi	Machine
Togetic	Machine
Natu	Machine
Xatu	Machine
Espeon	Machine
Slowking	Machine
Girafarig	Machine
Porygon2	Machine
Stantler	Machine
Smoochum	Machine
Lugia	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Meditite	Machine
Medicham	Machine
Solrock	Machine
Baltoy	Machine
Claydol	Machine
Chimecho	Machine
Metang	Machine
Metagross	Machine
Latias	Machine
Latios	Machine
Jirachi	Machine
Deoxys	Machine
Chingling	Machine
Bronzor	Machine
Bronzong	Machine
Mime Jr.	Machine
Togekiss	Machine
Porygon-Z	Machine
Gallade	Machine
Uxie	Machine
Mesprit	Machine
Azelf	Machine
Cresselia	Machine
Arceus	Machine
Victini	Machine
Munna	Machine
Musharna	Machine
Woobat	Machine
Swoobat	Machine
Audino	Machine
Sigilyph	Machine
Elgyem	Machine
Beheeyem	Machine
Meloetta	Machine
Aromatisse	Machine
Malamar	Machine
Sylveon	Machine
Klefki	Machine
Xerneas	Machine
Diancie	Machine
Hoopa	Machine
Oranguru	Machine
Solgaleo	Machine
Lunala	Machine
Nihilego	Machine
Necrozma	Machine
Blacephalon	Machine

Sun and Moon: 95 species

Species	Method	Level
Lunatone	Level up, Machine	1
Exeggutor	Level up, Machine	17
Gothita	Level up, Machine	25
Gothorita	Level up, Machine	25
Gothitelle	Level up, Machine	25
Solosis	Level up, Machine	25
Duosion	Level up, Machine	25
Reuniclus	Level up, Machine	25
Espurr	Level up, Machine	25
Meowstic	Level up, Machine	25
Fennekin	Level up, Machine	31
Tapu Lele	Level up, Machine	32
Braixen	Level up, Machine	36
Spoink	Level up, Machine	38
Delphox	Level up, Machine	38
Grumpig	Level up, Machine	42
Drowzee	Level up, Machine	57
Hypno	Level up, Machine	57
Clefairy	Machine
Clefable	Machine
Ninetales	Machine
Psyduck	Machine
Golduck	Machine
Abra	Machine
Kadabra	Machine
Alakazam	Machine
Slowpoke	Machine
Slowbro	Machine
Starmie	Machine
Mr. Mime	Machine
Jynx	Machine
Porygon	Machine
Mewtwo	Machine
Mew	Machine
Cleffa	Machine
Togepi	Machine
Togetic	Machine
Natu	Machine
Xatu	Machine
Espeon	Machine
Slowking	Machine
Girafarig	Machine
Porygon2	Machine
Stantler	Machine
Smoochum	Machine
Lugia	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Meditite	Machine
Medicham	Machine
Solrock	Machine
Baltoy	Machine
Claydol	Machine
Chimecho	Machine
Metang	Machine
Metagross	Machine
Latias	Machine
Latios	Machine
Jirachi	Machine
Deoxys	Machine
Chingling	Machine
Bronzor	Machine
Bronzong	Machine
Mime Jr.	Machine
Togekiss	Machine
Porygon-Z	Machine
Gallade	Machine
Uxie	Machine
Mesprit	Machine
Azelf	Machine
Cresselia	Machine
Arceus	Machine
Victini	Machine
Munna	Machine
Musharna	Machine
Woobat	Machine
Swoobat	Machine
Audino	Machine
Sigilyph	Machine
Elgyem	Machine
Beheeyem	Machine
Meloetta	Machine
Aromatisse	Machine
Malamar	Machine
Sylveon	Machine
Klefki	Machine
Xerneas	Machine
Diancie	Machine
Hoopa	Machine
Oranguru	Machine
Solgaleo	Machine
Lunala	Machine
Nihilego	Machine
Necrozma	Machine

Omega Ruby and Alpha Sapphire: 89 species

Species	Method	Level
Exeggutor	Level up, Machine	17
Gothita	Level up, Machine	25
Gothorita	Level up, Machine	25
Gothitelle	Level up, Machine	25
Solosis	Level up, Machine	25
Duosion	Level up, Machine	25
Reuniclus	Level up, Machine	25
Espurr	Level up, Machine	25
Meowstic	Level up, Machine	25
Fennekin	Level up, Machine	31
Braixen	Level up, Machine	34
Delphox	Level up, Machine	34
Spoink	Level up, Machine	38
Grumpig	Level up, Machine	42
Drowzee	Level up, Machine	57
Hypno	Level up, Machine	57
Clefairy	Machine
Clefable	Machine
Ninetales	Machine
Psyduck	Machine
Golduck	Machine
Abra	Machine
Kadabra	Machine
Alakazam	Machine
Slowpoke	Machine
Slowbro	Machine
Starmie	Machine
Mr. Mime	Machine
Jynx	Machine
Porygon	Machine
Mewtwo	Machine
Mew	Machine
Cleffa	Machine
Togepi	Machine
Togetic	Machine
Natu	Machine
Xatu	Machine
Espeon	Machine
Slowking	Machine
Girafarig	Machine
Porygon2	Machine
Stantler	Machine
Smoochum	Machine
Lugia	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Meditite	Machine
Medicham	Machine
Lunatone	Machine
Solrock	Machine
Baltoy	Machine
Claydol	Machine
Chimecho	Machine
Metang	Machine
Metagross	Machine
Latias	Machine
Latios	Machine
Jirachi	Machine
Deoxys	Machine
Chingling	Machine
Bronzor	Machine
Bronzong	Machine
Mime Jr.	Machine
Togekiss	Machine
Porygon-Z	Machine
Gallade	Machine
Uxie	Machine
Mesprit	Machine
Azelf	Machine
Cresselia	Machine
Arceus	Machine
Victini	Machine
Munna	Machine
Musharna	Machine
Woobat	Machine
Swoobat	Machine
Audino	Machine
Sigilyph	Machine
Elgyem	Machine
Beheeyem	Machine
Meloetta	Machine
Aromatisse	Machine
Malamar	Machine
Sylveon	Machine
Klefki	Machine
Xerneas	Machine
Diancie	Machine
Hoopa	Machine

X and Y: 89 species

Species	Method	Level
Exeggutor	Level up, Machine	17
Gothita	Level up, Machine	25
Gothorita	Level up, Machine	25
Gothitelle	Level up, Machine	25
Solosis	Level up, Machine	25
Duosion	Level up, Machine	25
Reuniclus	Level up, Machine	25
Espurr	Level up, Machine	25
Meowstic	Level up, Machine	25
Fennekin	Level up, Machine	31
Braixen	Level up, Machine	34
Delphox	Level up, Machine	34
Spoink	Level up, Machine	38
Grumpig	Level up, Machine	42
Drowzee	Level up, Machine	57
Hypno	Level up, Machine	57
Clefairy	Machine
Clefable	Machine
Ninetales	Machine
Psyduck	Machine
Golduck	Machine
Abra	Machine
Kadabra	Machine
Alakazam	Machine
Slowpoke	Machine
Slowbro	Machine
Starmie	Machine
Mr. Mime	Machine
Jynx	Machine
Porygon	Machine
Mewtwo	Machine
Mew	Machine
Cleffa	Machine
Togepi	Machine
Togetic	Machine
Natu	Machine
Xatu	Machine
Espeon	Machine
Slowking	Machine
Girafarig	Machine
Porygon2	Machine
Stantler	Machine
Smoochum	Machine
Lugia	Machine
Ralts	Machine
Kirlia	Machine
Gardevoir	Machine
Meditite	Machine
Medicham	Machine
Lunatone	Machine
Solrock	Machine
Baltoy	Machine
Claydol	Machine
Chimecho	Machine
Metang	Machine
Metagross	Machine
Latias	Machine
Latios	Machine
Jirachi	Machine
Deoxys	Machine
Chingling	Machine
Bronzor	Machine
Bronzong	Machine
Mime Jr.	Machine
Togekiss	Machine
Porygon-Z	Machine
Gallade	Machine
Uxie	Machine
Mesprit	Machine
Azelf	Machine
Cresselia	Machine
Arceus	Machine
Victini	Machine
Munna	Machine
Musharna	Machine
Woobat	Machine
Swoobat	Machine
Audino	Machine
Sigilyph	Machine
Elgyem	Machine
Beheeyem	Machine
Meloetta	Machine
Aromatisse	Machine
Malamar	Machine
Sylveon	Machine
Klefki	Machine
Xerneas	Machine
Diancie	Machine
Hoopa	Machine