New download cards for the upcoming Pokémon Ultra Sun and Ultra Moon games has included screenshots. Interestingly, on each card on the bottom left a Team Rocket member can be seen battling you.
It is possible that these appearances are merely a throwaway reference, much like how a memorable Team Rocket member can be found in Pokémon Black and White. Nonetheless, it’s an interesting observation. Are you hoping Team Rocket get themselves involved in the plot, or would you rather they stick to Kanto and Johto?
Thanks to Fletch for the tip.
Information from Serebii.net.