Pokémon Rising Ruby

Rising Ruby and Sinking Sapphire are modifications of Omega Ruby and Alpha Sapphire that allow you to play through the main game with all 721 Pokémon obtainable and go through the challenge of a significantly stronger Pokémon League. A huge emphasis has been placed on Pokémon availability, with most areas in the game offering 10 or 11 species that haven't been seen before that point. The mostly equal chance of encountering any of the Pokémon in an area also mean you're unlikely to get the same thing twice on the first encounter, making the game lend itself well to Nuzlocke runs (if you can handle the extra challenge from the trainer battles!).