Legend of the Arena is a pokemon game that has been being worked on for quite awhile. You should really check the game out.
The game was developed by “WackyTurtle,” the fan game focuses on a tournament, with pokemon Colosseum- style battles. It is pretty much an extended Elite Four. But yet there is history to it. Also your starter isn’t really chosen by you. You set your start by taking a personality test. Also the starters will be one of the eight Eevee Evolution.
The game does include mega evolution. But the Arenas take on mega’s are different. The feature doesn’t make your pokemon stronger. Mega pokemon are used as world-building mechanics.
For more info play the game (Below)