Final answer:
There are 48 unique Mega Evolutions available in certain Pokémon games, including Pokémon X and Y as well as Pokémon Omega Ruby and Alpha Sapphire.
Step-by-step explanation:
You asked how many mega evolutions there are in Pokémon. As of the current knowledge cutoff in 2023, there are a total of 48 unique Mega Evolutions in the Pokémon series. Mega Evolution is a special kind of transformation that affects certain Pokémon, allowing them to become more powerful during battle. However, it is important to note that this feature is specific to the games Pokémon X and Y, Pokémon Omega Ruby and Alpha Sapphire, and later appearances in some spin-off titles. The concept of Mega Evolution has not been carried into the newer generations such as in Pokémon Sword and Shield or Pokémon Legends: Arceus.