In Pokemon Legends: Z-A, players collect Mega Shards, but their purpose is not immediately clear.
The game introduces Mega Crystals, which can be shattered to obtain Mega Shards, through the tutorial in Lumiose City.
Mega Crystals are clusters of rock-like formations and pink shards, described as collections of Mega Energy.
The true purpose of collecting Mega Shards is not explained until later in the game.
Author's summary: Mega Shards in Pokemon Legends: Z-A.