I'm wondering what people think of Mew/Jolteon-EX/Glaceon-EX.
As a lockdown deck, you'd use the corresponding EX's attack to make Mew invincible during the opponent's turn (Jolteon for basics and Glaceon for evolutions). Dimension Valley cuts the attack costs down to two energy. Shaymin-EX can provide draw and Hoopa-EX grabs the Eeveelutions and Shaymin.
Ability lock stops Mew, but you've still got Jolteon and Glaceon in reserve who are respectable attackers in their own right. Lysandre also breaks the lock, so the strategy isn't fullproof. But it seems kinda cool.