Dark Void is learned by 1 species by level

Effect, in PokéAPI's words

“Puts the target to sleep.”

Who learns it

1 species in all, 8 of 11 games shown

Scarlet and Violet: 1 species

Species	Method	Level
Darkrai	Level up	66

Legends Arceus: 1 species

Species	Method	Level
Darkrai	Level up	57

Ultra Sun and Ultra Moon: 1 species

Species	Method	Level
Darkrai	Level up	66

Sun and Moon: 1 species

Species	Method	Level
Darkrai	Level up	66

Omega Ruby and Alpha Sapphire: 1 species

Species	Method	Level
Darkrai	Level up	66

X and Y: 1 species

Species	Method	Level
Darkrai	Level up	66

Black 2 and White 2: 1 species

Species	Method	Level
Darkrai	Level up	66

Black and White: 1 species

Species	Method	Level
Darkrai	Level up	66

Changed over time

One change since Generation IV

1. Through Gen VIAccuracy 80%50% from Sun and Moon, Generation VII