Z-move

Z-moves are a particularly powerful category of Pokemon moves that are performed in Pokémon Sun and Moon Abridged.

Characteristics
It seems that Z-moves require a Z-ring to be performed, as no character is ever seen performing one without possessing one. It most likely also requires a Z-crystal of some sort, but this is never clarified directly. Z-moves also seem to require specific dances to be executed.

In For a God's Sake it is revealed that Ash and Pikachu perfected a Z-move in the Hyperbolic Time Chamber (presumably) before arriving in Alola, indicating that Z-moves may be known in other parts of the Pokémon world. It is also possible that Z-moves are simply just very powerful Pokémon moves with no distinction from other types of attacks.

List of Z-Moves Performed

 * Kiawe and Gamera in The Milf, the Mime and the Maniac
 * Ash and Pikachu in For a God's Sake