I wondered if they would do this as a tie in when Ultra Sun and Ultra Moon were released, but apparently Niantic is going to randomly drop Alola form Pokémon on us in the near future. An official news item has been added to the game stating:
"Trainers, sunny days are ahead! Whether your forecast calls for rain or shine, we're celebrating all around the world by introducing some special Pokemon from the tropical Alola region to Pokémon GO! Get ready for some of the Pokémon originally discovered in the Kanto region to appear in their Alolan forms! These unique variants were first seen in the Pokémon Sun and Pokémon Moon video games, and they will make their way to Pokémon GO in the coming weeks. Keep an eye out for news related to this exciting change - and don't forget to tell your friends! Stay safe, and happy exploring!"
Here are some of the official images from Sun and Moon featuring the recent O.G. Kanto Pokémon with their updated forms.
May 21, 2018
I wondered if they would do this as a tie in when
April 25, 2018
Wow! When we started doing more and more community events I
October 23, 2017
My first raid bus was on August 12th, it was a RaidTX