If you're looking for a counter for decks that use a lot of energy, I would recommend Dedenne from Furious Fists, which does 20 damage times the number of energy attached to your opponent's active pokemon, or searches your deck for 2 basic pokemon and puts them on your bench. Both of these attacks cost one colorless energy each, so it can be used as a tech in any deck. It could be a bench liability with only 70 HP, but it could force your opponent to play the seven-prize game. The reason I like Dedenne is because it hits two of the biggest energy-stacking decks in the format for weakness, which are Lugia EX and Yveltal EX, and Yveltal EX is huge in the format. I usually include it in most of my decks if they have a bad Yveltal matchup, such as Trevenant, because it only takes up one slot. It doesn't help much against M Mewtwo EX (Psychic Infinity) as a tech to punish energy-stackers, but M Mewtwo EX is not as big in the format as Yveltal or Lugia.