Galvanic Key

Keening Stone

{5}, {T}: Target player mills X cards, where X is the number of cards in that player's graveyard.

Turnabout

Choose artifact, creature, or land. Tap all untapped permanents of the chosen type target player controls, or untap all tapped permanents of that type that player controls.

Disruption Protocol

As an additional cost to cast this spell, tap an untapped artifact you control or pay {1}.
Counter target spell.

Corridor Monitor

When Corridor Monitor enters, untap target artifact or creature you control.

Manifold Key

{1}, {T}: Untap another target artifact.
{3}, {T}: Target creature can't be blocked this turn.

Filigree Sages

Clock of Omens

Tap two untapped artifacts you control: Untap target artifact.

The Mindskinner

The Mindskinner can't be blocked.
If a source you control would deal damage to an opponent, prevent that damage and each opponent mills that many cards.