Urza, Chief Artificer

Affinity for artifact creatures (This spell costs {1} less to cast for each artifact creature you control.)
Artifact creatures you control have menace.
At the beginning of your end step, create a 0/0 colorless Construct artifact creature token with "This creature gets +1/+1 for each artifact you control."

Arcane Signet

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

Plague Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{T}: Add {C}.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Hovermyr

Timeless Lotus

Timeless Lotus enters tapped.
{T}: Add {W}{U}{B}{R}{G}.

Parasitic Implant

Enchant creature
At the beginning of your upkeep, enchanted creature's controller sacrifices it and you create a 1/1 colorless Phyrexian Myr artifact creature token.

Copper Myr

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Cryptolith Rite

Creatures you control have "{T}: Add one mana of any color."

Myr Matrix

Indestructible (Effects that say "destroy" don't destroy this artifact.)
Myr creatures get +1/+1.
{5}: Create a 1/1 colorless Myr artifact creature token.

Myr Galvanizer

Other Myr creatures you control get +1/+1.
{1}, {T}: Untap each other Myr you control.

Wake the Past

Return all artifact cards from your graveyard to the battlefield. They gain haste until end of turn.

Door to Nothingness

Door to Nothingness enters tapped.
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice Door to Nothingness: Target player loses the game.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Myr Enforcer

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Iron Myr

Urtet, Remnant of Memnarch

Whenever you cast a Myr spell, create a 1/1 colorless Myr artifact creature token.
At the beginning of combat on your turn, untap each Myr you control.
{W}{U}{B}{R}{G}, {T}: Put three +1/+1 counters on each Myr you control. Activate only during your turn.

Padeem, Consul of Innovation

Artifacts you control have hexproof. (They can't be the targets of spells or abilities your opponents control.)
At the beginning of your upkeep, if you control the artifact with the highest mana value or tied for the highest mana value, draw a card.

Alloy Myr

Palladium Myr

Gold Myr

Darksteel Myr

Indestructible (Damage and effects that say "destroy" don't destroy this creature. If its toughness is 0 or less, it's still put into its owner's graveyard.)

Karn, Legacy Reforged

Karn, Legacy Reforged's power and toughness are each equal to the greatest mana value among artifacts you control.
At the beginning of your upkeep, add {C} for each artifact you control. This mana can't be spent to cast nonartifact spells. Until end of turn, you don't lose this mana as steps and phases end.

Shimmer Dragon

Flying
As long as you control four or more artifacts, Shimmer Dragon has hexproof. (It can't be the target of spells or abilities your opponents control.)
Tap two untapped artifacts you control: Draw a card.

Tempered Steel

Artifact creatures you control get +2/+2.

Jhoira, Weatherlight Captain

Whenever you cast a historic spell, draw a card. (Artifacts, legendaries, and Sagas are historic.)

Cyberman Patrol

Artifact creatures you control have afflict 3. (Whenever a creature with afflict 3 becomes blocked, defending player loses 3 life.)

Dispatch

Tap target creature.
Metalcraft — If you control three or more artifacts, exile that creature.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Leaden Myr

Alibou, Ancient Witness

Other artifact creatures you control have haste.
Whenever one or more artifact creatures you control attack, Alibou, Ancient Witness deals X damage to any target and you scry X, where X is the number of tapped artifacts you control.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Kindred Discovery

As Kindred Discovery enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, 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.

Their Name Is Death

Thoughtcast

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Draw two cards.

Myr Kinsmith

When Myr Kinsmith enters, you may search your library for a Myr card, reveal it, put it into your hand, then shuffle.

Myr Convert

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
{T}, Pay 2 life: Add one mana of any color.

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Ichorclaw Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever Ichorclaw Myr becomes blocked, it gets +2/+2 until end of turn.

Genesis Chamber

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

Lodestone Myr

Trample
Tap an untapped artifact you control: Lodestone Myr gets +1/+1 until end of turn.

Organic Extinction

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Destroy all nonartifact creatures.

Vedalken Archmage

Whenever you cast an artifact spell, draw a card.

Myr Reservoir

{T}: Add {C}{C}. Spend this mana only to cast Myr spells or activate abilities of Myr.
{3}, {T}: Return target Myr card from your graveyard to your hand.

Myr Battlesphere

When Myr Battlesphere enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever Myr Battlesphere attacks, you may tap X untapped Myr you control. If you do, Myr Battlesphere gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Losheel, Clockwork Scholar

Prevent all combat damage that would be dealt to attacking artifact creatures you control.
Whenever one or more artifact creatures you control enter, draw a card. This ability triggers only once each turn.

Silver Myr

Unwinding Clock

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

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Thirst for Knowledge

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

Myr Welder

Imprint — {T}: Exile target artifact card from a graveyard.
Myr Welder has all activated abilities of all cards exiled with it.

Foundry Inspector

Artifact spells you cast cost {1} less to cast.

Myr Turbine

{T}: Create a 1/1 colorless Myr artifact creature token.
{T}, Tap five untapped Myr you control: Search your library for a Myr creature card, put it onto the battlefield, then shuffle.

Sol Ring

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Counterspell

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

Negate

Etherium Sculptor

Shimmer Myr

Flash
You may cast artifact spells as though they had flash.

Steel Overseer

{T}: Put a +1/+1 counter on each artifact creature you control.

Myr Retriever

When Myr Retriever dies, return another target artifact card from your graveyard to your hand.

All Is Dust

Each player sacrifices all permanents they control that are one or more colors.

Myr Superion

Spend only mana produced by creatures to cast this spell.

Myrsmith

Whenever you cast an artifact spell, you may pay {1}. If you do, create a 1/1 colorless Myr artifact creature token.