Howling Mine

At the beginning of each player's draw step, if this artifact is untapped, that player draws an additional card.

Blood Moon

Winter Orb

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

Static Orb

As long as this artifact is untapped, players can't untap more than two permanents during their untap steps.

Unwinding Clock

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

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.