>>50801937/mlp/ usually get pics like OP from the pony boorus.
Twibooru/Ponybooru looks like the most popular ones since their filters are very open. I bet you can put pokemon in the search bar and you will find lots of ppny x poke fanart.
In fact, I think recently a guy did their own pokepony game. You have a "pony/eevee", and you must find crystals to change its typing. Sounds interesting, but is still on demo mode.
