There are tons of Pokémon fan games out there. You can find many variations out there which add more pokemons or more interesting fights to the older games but nobody had previously made a whole game with a different adventure and totally new Pokémons.
A couple of fans, JVUranium and Voluntarytwitch, decided to work on an entirely new Pokémon game called Pokémon Uranium, which includes features like 150 new custom Pokémon, the ability to talk to your Pokémon, a new type: Nuclear and a super cool feature which no other previous Pokémon rom game had – trading and batteling with other trainers online! The game takes place in a tropical setting. It was an ambitious prjoect which took NINE YEARS to complete.
The version 1.0 of the game is done but no more available on the official site. The makers decided to remove the download link after 1.5 million downloads and a few tussles with nintendo over copyright issues. Don’t freak out, you can still find them on torrent sites. The game is currently available only for Windows at the moment and will require an emulator like the previous games.
To check out new Pokémons and to stay updated on the game’s status, check out the official site.