https://www.gamespot.com/articles/pokemon-go-to-add-generation-3-creatures-very-soon/1100-6454093/

The Halloween event might not have been revealed yet, but another is currently ongoing. Until October 25, the best AR photos taken in-game have the chance of winning some cool prizes. Finally, Pokemon Go's Legendary Dogs have switched location. This time, players in the Americas will have a chance to catch the Fire-type Entei; the Water-type Suicune has moved to Europe and Africa; and the Electric-type Raikou can be found in the Asia-Pacific region. The three Pokemon will remain in their current location until October 31; on that date, the Legendaries will rotate to their final region, where they'll be available until November 30.

What other creatures from Hoenn and Pokemon Ruby / Sapphire would you like to see added to Pokemon Go? Let us know in the comments below!