On their turn, a player can place a single energy on a Pokmon, perform an attack with an active Pokmon, play Pokmon onto their bench or play item or trainer cards from their hand
Because so many decks run Light and Dark monsters, it's reasonable to expect the player will always have a way to summon Bystials
I think its reasonable to assume that its anyones guess as to what kind of things could get printed
NOEX - For Those Who Battle With Honour For those who want to face others who share a similar disdain for the overused EX cards, they can join a Private Lobby by inputting the password NOEX. While this is based on an honor system and isnt an officially implemented game mode, it can display the impressive amount of decks available in Pokemon TCG Pocket
Card Set(s) -WINGS OF THE CAPTAIN-[OP06] CARD VIEW OP06-018 | R | EVENT Gum-Gum King Kong Gatling Block icon 2 Effect [Main] Up to 1 of your Leader or Character cards gains +3000 power during this turn
Consider this write-up to be a Magic players guide to Arena