Pokemon Azul

The player character starts out in Pallet Town. When the player character tries to leave the town without a Pokémon of their own, they are stopped in the nick of time by Professor Oak, who invites them to his lab. There, he gives them a Pokémon of their own and a Pokédex, telling them about his dream to make a complete guide on every Pokémon in the world. After the player character battles their rival and leaves the lab, they are entitled to win every Gym Badge, compete in the Pokémon League, and fulfill Oak's dream by catching every Pokémon.