Dyfed, the Guiding Hand [Mystery Booster: Commander Edition]

+1: Create two tapped Powerstone tokens. (They're artifacts with "T: Add C. This mana can't be spent to cast a nonartifact spell.")
−X: Untap X target artifacts.
−6: Search your library for an artifact card, put it onto the battlefield, then shuffle.
Dyfed, the Guiding Hand can be your commander.