Pokémon : Rising Crystal

Pokémon Rising Crystal is an enhancement hack of Pokémon Crystal that aims to improve many of the flaws that the original GSC had, while also not deviating too much in style and feel. Story elements are kept mostly the same with a few additions.

The original Gen 2 cast of Pokémon have been overhauled to allow for more diversity in the available types of Pokémon, so that certain types aren't under-represented. Many Pokémon have had their types, stats and appearance altered to make them more viable for use in a playthrough. Some Pokémon additionally have brand new original evolutions to give them more end-game viability.

Source: TheGamesDB