Netflix is losing almost all of its Pokemon content.
The popular streaming service will lose the first season of Pokemon: Indigo League, both seasons of Pokemon the Series: X & Y, plus the movies Pokemon the Movie: Hoopa and the Clash of Ages and Pokemon the Movie: Diancie and the Cocoon of Destruction.
That will leave Pokemon the Series: X Y & Z (which serves as a third season of Pokemon the Series: X & Y) as the only Pokemon content currently available on Netflix come January 2018.
The loss of the Pokemon series is disappointing, but shouldn't come as too big of a surprise. When Disney obtained the rights to the Pokemon franchise in 2016, it seemed likely that Disney would eventually want to take control of the on demand aspects of the show. With the rights to all 21 seasons of the Pokemon anime and 20 different movies, we will probably see Pokemon pop up on Disney's planned streaming service, which is due to launch in 2019.
If you're still looking to catch Pokemon on demand, you can watch individual episodes via the Pokemon TV app. The Pokemon TV app airs both "new" episodes of Pokemon the Series: Sun and Moon (delayed by about a month) and older episodes that all share a common theme. The app also periodically adds episodes of older series so that fans can gradually catch up on Ash's original episodes.