Genesis Chamber

Whenever a nontoken creature enters, if Genesis Chamber is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Unwinding Clock

Untap all artifacts you control during each other player's untap step.

Winter Orb

As long as Winter Orb is untapped, players can't untap more than one land during their untap steps.

Meria, Scholar of Antiquity

Tap an untapped nontoken artifact you control: Add {G}.
Tap two untapped nontoken artifacts you control: Exile the top card of your library. You may play it this turn.

Voltaic Servant

At the beginning of your end step, untap target artifact.