As the number of Pokémon games has grown over the last 25 years, so have the regions comprising the Pokémon universe. What began in Kanto has expanded to seven more regions in the mainline games: Johto, Hoenn, Sinnoh, Unova, Kalos, Alola, and Galar. But there is even more to Pokémon than the mainline games. As the series has inspired spin-offs, many additional regions have come to comprise the Pokémon world.
Most Pokémon spin-off games create their own regions, and they often do so to create the game's central gimmick. For example, the newest region in Pokémon is Aeos Island, which will be the setting for the upcoming MOBA Pokémon UNITE. Aeos itself is the central mechanic for UNITE, because it is the sole home of Aeos energy, which is created by defeating Pokémon and can be subsequently used to power up one's own.
Aeos Island is just the most recent iteration of a trend. New Pokémon Snap introduced the Lental region, a chain of islands which house the mysterious Illumina phenomenon. Pokémon Island from the original Pokémon Snap is a Pokémon sanctuary. Trainers, along with most other humans, aren't allowed to travel to the island, making it a perfect location for Pokémon photography.
Every Pokémon Spin-Off Region That's Appeared So Far
The universe expansion afforded by Pokémon's spin-offs go well beyond Aeos, Lental, and Pokémon Island. Even the newly re-popularized Pokémon Trading Card Game has included packs which create their own regions: Holon and the Southern Islands. This is not to be confused with the 2000 release of the Pokémon Trading Card Game for Game Boy Color, which added the Trading Card Game Islands to the series.
As Aeos Island suggests, island nations are a popular location for Pokémon spin-offs. Pokémon Duel takes place on the man-made Carmonte Island, which is known for its luxury resorts. Pokémon Masters EX also takes place on an artificial island. This one, Pasio, was constructed on one man's whims to host the Pokémon Masters League. Even the most absurd ideas, like having an area populated only by cube-shaped Pokémon, can be explained if it happens in an isolated island, like Pokémon Quest's Tumblecube Island. The Pokémon anime also created two island regions, the Orange Archipelago and the Decolore Islands. However, the anime explains exactly where they lay in relation to Kanto.
Other spin-offs create entire regions. The Pokémon Ranger series alone is responsible for Fiore, Almia, and Oblivia. These three regions distinguish themselves by the absence of Pokémon Trainers and Poké Balls. opting instead of a team of Pokémon Rangers to help people and Pokémon co-exist. The two Generation III side games, Pokémon Colosseum and Pokémon XD: Gale of Darkness, take place in Orre, a more remote-feeling region with no official Pokémon League. Even the crossover game Pokémon Conquest and the Tekken-inspired Pokken Tournament create their own expansive regions - Ransei and Ferrum, respectively.
There are extraneous cities in spin-offs whose exact locations are unknown, but could be part of mainline Pokémon regions. Mintale Town from Pokémon Channel, for instance, is thought to be in Kanto because it mentions Viridian Forest. While the original Pokémon Stadium does not specify a setting at all, Pokémon Stadium 2 introduces White City. The regional location of Rhyme City from the film Detective Pikachu is also unknown. Most perplexing of all is the setting of the Pokémon Mystery Dungeon series, which appears to take place on an entirely different planet where humans do not exist.
The world beyond the eight regions of the mainline Pokémon games is vast. Spin-offs create a rich tapestry of different cultures and alternatives to the Pokémon Trainer route central to the mainline games. They even offer an entire planet populated only by Pokémon. And, since there is sure to be no shortage of new Pokémon games in the future, this universe will only keep expanding.