They might Leyline of the Void you
Thats great for players who actually sink $99 into whole boxes
Frankenderp" once per turn
Skill cards of Jaden Yuki, Aster Phoenix, Chazz Princeton, Alexis Rhodes and others are included along with their signature monster and Deck strategies

Heres a short list of all the important cards featured in each set: HGSS: Cleffa, Tyrogue, Jumpluff, Ninetales, Pichu, Pokmon Collector, Pokmon Communication, Professor Oaks New Theory, Copycat, Rainbow Energy, Double Colorless Energy, Donphan Prime, Typhlosion Prime, Blissey Prime UL: Rare Candy, Jirachi, Suicune/Entei Legend, Shaymin, Kingdra Prime, Tyranitar Prime, Lanturn Prime, Judge UD: Sages Training, Vileplume, Weavile, Rayquaza/Deoxys Legend, Muk, Sages Training TM: Junk Arm, Seeker, Twins, Rescue Energy, Almost Every Single Prime (Magnezone, Mew, Yanmega, Gengar, etc.) CoL: Jirachi, Pachirisu, Cleffa, Tyrogue, Ninetales, Sages Training, Professor Oaks New Theory BW: Emboar, Reshiram, Zekrom, Cinccino, Reuniclus, Zoroark, Pokmon Communication, Professor Juniper EP: Pokmon Catcher, Tornadus, Gothitelle, Cheren This is just an introductory list, but Im sure just by looking at it its easy to see how tough it can be to build a deck

Its better to use it as a solution to certain metagames