The XY Primal Clash expansion set was released in February 2015. It’s a big set with a total of 164 cards… 160 + 4 secret rares. Some of the more valuable cards are the 24 Pokemon EX cards (4 of which are Mega EX) and the 4 secret rare items.
Primal Clash Set List
Complete list of cards in the Pokemon XY Primal Clash expansion set.