Darkrai EX and Magnezone

Darkrai EX and Magnezone have stupid-good synergy, though the real highlight card here MAY be Magneton. While Darkrai sets itself up and takes pot-shots, Magneton will generate its own Electric energy, meaning you'll likely have 2 high-performance cards set up and ready to go at about the same time at the cost of 1. Druddigon can act as a powerful wall that racks up bits of damage while everything gets set up.

Note: you should only have Dark energy on this deck, as Magneton is self-sufficient in terms of Electric energy.