Clock of Omens

Tap two untapped artifacts you control: Untap target artifact.

Copperhorn Scout

Whenever this creature attacks, untap each other creature you control.

Endbringer

Untap this creature during each other player's untap step.
{T}: This creature deals 1 damage to any target.
{C}, {T}: Target creature can't attack or block this turn.
{C}{C}, {T}: Draw a card.

Ghirapur Aether Grid

Tap two untapped artifacts you control: This enchantment deals 1 damage to any target.

Akki Battle Squad

Whenever one or more modified creatures you control attack, untap all modified creatures you control. After this phase, there is an additional combat phase. This ability triggers only once each turn. (Equipment, Auras you control, and counters are modifications.)

Genesis Chamber

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

Cacophodon

Enrage — Whenever this creature is dealt damage, untap target permanent.

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.

Howling Mine

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

Dermotaxi

Imprint — As this Vehicle enters, exile a creature card from a graveyard.
Tap two untapped creatures you control: Until end of turn, this Vehicle becomes a copy of the exiled card, except it's a Vehicle artifact in addition to its other types.

Angel's Trumpet

All creatures have vigilance.
At the beginning of each player's end step, tap all untapped creatures that player controls that didn't attack this turn. This artifact deals damage to the player equal to the number of creatures tapped this way.

Emerald Charm

Choose one —
• Untap target permanent.
• Destroy target non-Aura enchantment.
• Target creature loses flying until end of turn.

Earthcraft

Tap an untapped creature you control: Untap target basic land.

Benefactor's Draught

Untap all creatures. Until end of turn, whenever a creature an opponent controls blocks, draw a card.
Draw a card.

Elmar, Ulvenwald Informant

Haste
Whenever you cast your second spell each turn, untap target creature, then investigate. (Create a colorless Clue artifact token with "{2}, Sacrifice this artifact: Draw a card.")
Friends forever (You can have two commanders if both have friends forever.)

Insurrection

Untap all creatures and gain control of them until end of turn. They gain haste until end of turn.

Blinkmoth Urn

At the beginning of each player's first main phase, if this artifact is untapped, that player adds {C} for each artifact they control.

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.