PoT is good in Zoroark, but I think its almost never going to be worth it without ways to draw into them. Mallow comes to mind, but requires you to not already have used Trade(s) and requires abilities to be turned on. Skyla, on the other hand, does not require trade, but also requires you to already have a PoT in your hand. As for Mallow and Skyla in general, I think Mallow would generally be better because Skyla can only fetch Trainers, while Mallow can get you anything. However, beware of ability lock, cos thatd hurt :V