Unwinding Clock

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

Coldsteel Heart

Coldsteel Heart enters tapped.
As Coldsteel Heart enters, choose a color.
{T}: Add one mana of the chosen color.

Aphetto Alchemist

{T}: Untap target artifact or creature.
Morph {U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Pemmin's Aura

Enchant creature
{U}: Untap enchanted creature.
{U}: Enchanted creature gains flying until end of turn.
{U}: Enchanted creature gains shroud until end of turn. (It can't be the target of spells or abilities.)
{1}: Enchanted creature gets +1/-1 or -1/+1 until end of turn.

Fomori Vault

{T}: Add {C}.
{3}, {T}, Discard a card: Look at the top X cards of your library, where X is the number of artifacts you control. Put one of those cards into your hand and the rest on the bottom of your library in a random order.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Mirrodin Besieged

As Mirrodin Besieged enters, choose Mirran or Phyrexian.
• Mirran — Whenever you cast an artifact spell, create a 1/1 colorless Myr artifact creature token.
• Phyrexian — At the beginning of your end step, draw a card, then discard a card. Then if there are fifteen or more artifact cards in your graveyard, target opponent loses the game.

Thirst for Knowledge

Draw three cards. Then discard two cards unless you discard an artifact card.

Freed from the Real

Enchant creature
{U}: Tap enchanted creature.
{U}: Untap enchanted creature.

Archaeomender

When Archaeomender enters, return target artifact card from your graveyard to your hand.

Sol Ring

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Worldwalker Helm

If you would create one or more artifact tokens, instead create those tokens plus an additional Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")
{1}{U}, {T}: Create a token that's a copy of target artifact token you control.

Urza, Powerstone Prodigy

Vigilance
{1}, {T}: Draw a card, then discard a card.
Whenever you discard one or more artifact cards, create a tapped Powerstone token. This ability triggers only once each turn. (The token is an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Emry, Lurker of the Loch

This spell costs {1} less to cast for each artifact you control.
When Emry, Lurker of the Loch enters, mill four cards.
{T}: Choose target artifact card in your graveyard. You may cast that card this turn. (You still pay its costs. Timing rules still apply.)

Sky Diamond

Riddlesmith

Whenever you cast an artifact spell, you may draw a card. If you do, discard a card.

Second Wind

Enchant creature
{T}: Tap enchanted creature.
{T}: Untap enchanted creature.

Careful Study

Stern Lesson

Draw two cards, then discard a card. Create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")