In the post game of PLA there is a battle facility run by Ingo and you can rematch most of the trainers in the game
There is a really long side question that involves finding all the unown forms all over Hisui. They are static encounters and you can keep track of the ones you caught in your pokedex
The new Linking Cord item in action being used to evolve a Kadabra. It is a consumable item like an evolution stone.
https://www.reddit.com/r/PokeLeaks/comments/s8zf3t/you_can_now_evolve_trade_evo_mons_with_an_item/?s=09SwSh/BDSM game data is required to obtain Darkrai/Shaymin in the post game
