As for the most valuable chase cards you can get (or buy individually on TCGplayer ), the top five right now are SIR Mega Darkrai ex, MHR Mega Darkrai ex, SIR Mega Morpeko ex, Mega Zeraora ex, and SIR Mega Chandelure ex
3) Rules Lawyer The stuffy card equivalent of That One Person in your gaming group who won't quit trying to search for loopholes
However, I'd put $5 on Sylveon ex being the most powerful card from the set - it's Pokmon Pocket's first real draw engine, acting like a Professor Oak and drawing you two cards the turn you play it
Named after the Sonic Heroes enemy, Egg Hammer is a skin of Myr Battlesphere
Maybe then you could probably lessen up on the LP-cost, since the huge amount of restrictions would just mean that you lose Life Points for something your opponent can easily take out if you don't have enough protection cards.
Four new promo cards are on the horizon with Surging Sparks