Karn, the Great Creator

Activated abilities of artifacts your opponents control can't be activated.
+1: Until your next turn, up to one target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.
−2: You may reveal an artifact card you own from outside the game or choose a face-up artifact card you own in exile. Put that card into your hand.

Seal of Cleansing

Sacrifice this enchantment: Destroy target artifact or enchantment.

Mycosynth Lattice

All permanents are artifacts in addition to their other types.
All cards that aren't on the battlefield, spells, and permanents are colorless.
Players may spend mana as though it were mana of any color.

Lion's Eye Diamond

Discard your hand, Sacrifice this artifact: Add three mana of any one color. Activate only as an instant.

The One Ring

Indestructible
When The One Ring enters, if you cast it, you gain protection from everything until your next turn.
At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring.
{T}: Put a burden counter on The One Ring, then draw a card for each burden counter on The One Ring.

Paradox Engine

Whenever you cast a spell, untap all nonland permanents you control.

Lotus Petal

{T}, Sacrifice this artifact: Add one mana of any color.

Ensnaring Bridge

Creatures with power greater than the number of cards in your hand can't attack.

Crystal Vein

{T}: Add {C}.
{T}, Sacrifice this land: Add {C}{C}.

Walking Ballista

This creature enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on this creature.
Remove a +1/+1 counter from this creature: It deals 1 damage to any target.

Eiganjo, Seat of the Empire

{T}: Add {W}.
Channel — {2}{W}, Discard this card: It deals 4 damage to target attacking or blocking creature. This ability costs {1} less to activate for each legendary creature you control.

Mox Diamond

If this artifact would enter, you may discard a land card instead. If you do, put this artifact onto the battlefield. If you don't, put it into its owner's graveyard.
{T}: Add one mana of any color.

Serum Powder

{T}: Add {C}.
Any time you could mulligan and this card is in your hand, you may exile all the cards from your hand, then draw that many cards. (You can do this in addition to taking mulligans.)

Voltaic Key

City of Traitors

When you play another land, sacrifice this land.
{T}: Add {C}{C}.

Candelabra of Tawnos

Portable Hole

When this artifact enters, exile target nonland permanent an opponent controls with mana value 2 or less until this artifact leaves the battlefield.

Manifold Key

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

Mystic Forge

You may look at the top card of your library any time.
You may cast artifact spells and colorless spells from the top of your library.
{T}, Pay 1 life: Exile the top card of your library.

Soul Partition

Exile target nonland permanent. For as long as that card remains exiled, its owner may play it. A spell cast by an opponent this way costs {2} more to cast.

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.

Defense Grid

Each spell costs {3} more to cast except during its controller's turn.

Karakas

{T}: Add {W}.
{T}: Return target legendary creature to its owner's hand.

Ancient Tomb

{T}: Add {C}{C}. This land deals 2 damage to you.

Glaring Fleshraker

Whenever you cast a colorless spell, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."
Whenever another colorless creature you control enters, this creature deals 1 damage to each opponent.

Grim Monolith

This artifact doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{4}: Untap this artifact.

Plains

Basalt Monolith

This artifact doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap this artifact.

Touch the Spirit Realm

When this enchantment enters, exile up to one target artifact or creature until this enchantment leaves the battlefield.
Channel — {1}{W}, Discard this card: Exile target artifact or creature. Return it to the battlefield under its owner's control at the beginning of the next end step.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — This Saga gains "{T}: Add {C}."
II — This Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This token gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Semblance Anvil

Imprint — When this artifact enters, you may exile a nonland card from your hand.
Spells you cast that share a card type with the exiled card cost {2} less to cast.