Power Gem is learned by 31 species by level, 70 by machine and 1 by egg

Effect, in PokéAPI's words

“Inflicts regular damage with no additional effect.”

Who learns it

70 species in all, 8 of 13 games shown

Scarlet and Violet: 59 species

Species	Method	Level
Persian	Level up, Machine	Evolve
Slowking	Level up, Machine	1
Mismagius	Level up, Machine	1
Nosepass	Level up, Machine	25
Probopass	Level up, Machine	25
Mareep	Level up, Machine	29
Spoink	Level up, Machine	29
Grumpig	Level up, Machine	29
Vespiquen	Level up, Machine	32
Flaaffy	Level up, Machine	34
Ampharos	Level up, Machine	35
Glimmet	Level up, Machine	37
Minior	Level up, Machine	38
Sableye	Level up, Machine	39
Glimmora	Level up, Machine	39
Carbink	Level up, Machine	45
Gholdengo	Level up, Machine	49
Misdreavus	Level up, Machine	50
Dialga	Level up, Machine	56
Palkia	Level up, Machine	56
Flutter Mane	Level up, Machine	56
Diancie	Level up, Machine	63
Necrozma	Level up, Machine	64
Meowth	Machine
Golduck	Machine
Mewtwo	Machine
Mew	Machine
Sudowoodo	Machine
Espeon	Machine
Slugma	Machine
Magcargo	Machine
Tyranitar	Machine
Regirock	Machine
Shieldon	Machine
Bastiodon	Machine
Bronzor	Machine
Bronzong	Machine
Bonsly	Machine
Gabite	Machine
Garchomp	Machine
Heatran	Machine
Cresselia	Machine
Arceus	Machine
Rolycoly	Machine
Carkol	Machine
Coalossal	Machine
Stonjourner	Machine
Meowscarada	Machine
Nacli	Machine, Egg
Naclstack	Machine
Garganacl	Machine
Klawf	Machine
Rabsca	Machine
Bombirdier	Machine
Sandy Shocks	Machine
Iron Thorns	Machine
Gimmighoul	Machine
Miraidon	Machine
Terapagos	Machine

Legends Arceus: 7 species

Species	Method	Level
Dialga	Level up	27
Palkia	Level up	27
Misdreavus	Level up	34
Nosepass	Level up	34
Vespiquen	Level up	34
Mismagius	Level up	34
Probopass	Level up	34

Brilliant Diamond and Shining Pearl: 18 species

Species	Method	Level
Persian	Level up	Evolve, 1
Starmie	Level up	1
Slowking	Level up	1
Mismagius	Level up	1
Nosepass	Level up	25
Probopass	Level up	25
Mareep	Level up	29
Spoink	Level up	29
Grumpig	Level up	29
Vespiquen	Level up	32
Flaaffy	Level up	34
Ampharos	Level up	35
Staryu	Level up	36
Sableye	Level up	39
Corsola	Level up	40
Misdreavus	Level up	55
Dialga	Level up	64
Palkia	Level up	64

Sword and Shield: 21 species

Species	Method	Level
Persian	Level up, Machine	Evolve, 1
Boldore	Level up, Machine	Evolve, 1
Starmie	Level up, Machine	1
Slowking	Level up, Machine	1
Gigalith	Level up, Machine	1
Vespiquen	Level up, Machine	32
Staryu	Level up, Machine	36
Sableye	Level up, Machine	39
Corsola	Level up, Machine	40
Cursola	Level up, Machine	40
Carbink	Level up, Machine	45
Nihilego	Level up, Machine	50
Dialga	Level up, Machine	56
Palkia	Level up, Machine	56
Diancie	Level up, Machine	63
Necrozma	Level up, Machine	64
Mew	Machine
Lunatone	Machine
Klink	Machine
Klang	Machine
Klinklang	Machine

Ultra Sun and Ultra Moon: 25 species

Species	Method	Level
Boldore	Level up	Evolve, 1
Slowking	Level up	1
Lunatone	Level up	1
Mismagius	Level up	1
Gigalith	Level up	1
Dialga	Level up	19
Palkia	Level up	19
Nosepass	Level up	25
Vespiquen	Level up	25
Probopass	Level up	25
Mareep	Level up	29
Spoink	Level up	29
Grumpig	Level up	29
Persian	Level up	32
Flaaffy	Level up	34
Ampharos	Level up	35
Sableye	Level up	36
Staryu	Level up	37
Nihilego	Level up	37
Minior	Level up	38
Diancie	Level up	40
Corsola	Level up	41
Necrozma	Level up	43
Carbink	Level up	46
Misdreavus	Level up	55

Sun and Moon: 25 species

Species	Method	Level
Boldore	Level up	Evolve, 1
Slowking	Level up	1
Lunatone	Level up	1
Mismagius	Level up	1
Gigalith	Level up	1
Dialga	Level up	19
Palkia	Level up	19
Nosepass	Level up	25
Vespiquen	Level up	25
Probopass	Level up	25
Mareep	Level up	29
Spoink	Level up	29
Grumpig	Level up	29
Persian	Level up	32
Flaaffy	Level up	34
Ampharos	Level up	35
Sableye	Level up	36
Staryu	Level up	37
Nihilego	Level up	37
Minior	Level up	38
Diancie	Level up	40
Corsola	Level up	41
Necrozma	Level up	43
Carbink	Level up	46
Misdreavus	Level up	55

Omega Ruby and Alpha Sapphire: 20 species

Species	Method	Level
Slowking	Level up	1
Mismagius	Level up	1
Dialga	Level up	19
Palkia	Level up	19
Nosepass	Level up	25
Vespiquen	Level up	25
Probopass	Level up	25
Boldore	Level up	25
Gigalith	Level up	25
Mareep	Level up	29
Spoink	Level up	29
Grumpig	Level up	29
Persian	Level up	32
Flaaffy	Level up	34
Ampharos	Level up	35
Sableye	Level up	36
Staryu	Level up	37
Corsola	Level up	41
Carbink	Level up	46
Misdreavus	Level up	55

X and Y: 20 species

Species	Method	Level
Slowking	Level up	1
Mismagius	Level up	1
Dialga	Level up	19
Palkia	Level up	19
Vespiquen	Level up	25
Boldore	Level up	25
Gigalith	Level up	25
Mareep	Level up	29
Persian	Level up	32
Nosepass	Level up	32
Probopass	Level up	32
Spoink	Level up	33
Flaaffy	Level up	34
Ampharos	Level up	35
Grumpig	Level up	35
Corsola	Level up	41
Staryu	Level up	43
Sableye	Level up	43
Carbink	Level up	46
Misdreavus	Level up	55

Changed over time

One change since Generation IV

1. Through Gen VPower 7080 from X and Y, Generation VI