Pokémon Ruby and Sapphire introduced 135 new Pokémon in the third generation.
These species expanded the series from 251 Pokémon after Generation II to 386 total species. The new designs begin with the starter Pokémon Treecko, Torchic, and Mudkip and continue through the Hoenn Pokédex to Deoxys.
Ruby and Sapphire also changed the structure of Pokémon battles and exploration. They introduced Pokémon Abilities, which give species or individuals special effects, along with double battles, Pokémon Contests, Secret Bases, and a selectable protagonist gender. The games also added a more detailed visual style through the capabilities of the Game Boy Advance.
The games were released in Japan in November 2002 and internationally in 2003. Their 135 new species are separate from later additions in Pokémon Emerald, which is an enhanced version rather than a new generation.