Available since August 27, 2020 on Pokémon GO, the functionality of Mega-Evolution was already known to other games of the license since the generation of Kalos. The principle still changes a little since now you will have to collect Mega-Energy in order to Mega-Evolve your creatures.
To get them, you must participate in Mega Raids. Below is a list of currently available Raids, and Mega Evolutions that will arrive sooner or later in the game.
List of available Mega-Evolutions
200 Mega Blastoise Energy needed
Water
200 Charizard Mega-Energy needed
Fire and Dragon
200 Charizard Mega-Energy needed
Fire and Flying types
200 Venusaur Mega-Energy needed
Grass and Poison Types
100 Beedrill Mega-Energy needed
Bug and Poison
List of non existing Mega-Evolutions
These Mega Evolutions are not yet available in the game but sooner or later will be.
Normal and Flying types
Psychic type
Water and Psy Types
Ghost and Poison Types
Normal Type
Types Bug and Flying
Water and Dark Types
Rock and Flying types
Psychic and Fighting Types
Psychic type
Electric and Dragon types
Steel and Ground Types
Types Bug and Steel
Bug and Fighting Types
Dark and Fire
Rock and Dark Types
Grass and Dragon types
Fire and Fighting Types
Water and Ground Types
Psychic and Fairy types
Dark and Ghost
Steel and Fairy types
Steel
Fighting and Psychic types
Electric type
Water and Dark Types
Fire and Ground Types
Dragon and Fairy types
Ghost type
Dark type
Ice Type
Dragon and Flying types
Steel and Psychic types
Dragon and Psychic types
Dragon and Flying types
Normal and Fighting types
Dragon and Ground types
Fighting and Steel Types
Grass and Ice Types
Psychic and Fighting Types
Normal and Fairy types
Rock and Fairy types
