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.

Lux Artillery

Whenever you cast an artifact creature spell, it gains sunburst. (It enters the battlefield with a +1/+1 counter on it for each color of mana spent to cast it.)
At the beginning of your end step, if there are thirty or more counters among artifacts and creatures you control, Lux Artillery deals 10 damage to each opponent.

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.

All Is Dust

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

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Spellbook

Carnage Altar

Manifold Key

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

Chromatic Lantern

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

The Mycosynth Gardens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{X}, {T}: The Mycosynth Gardens becomes a copy of target nontoken artifact you control with mana value X.

Palladium Myr

Myr Custodian

When Myr Custodian enters the battlefield, scry 2. Then each opponent may scry 1. (To scry X, that player looks at the top X cards of their library, then put any number of them on the bottom and the rest on top in any order.)

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Exotic Orchard

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

Path of Ancestry

Path of Ancestry enters the battlefield tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Perilous Myr

When Perilous Myr dies, it deals 2 damage to any target.

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.

Ashnod's Altar

Retract

Return all artifacts you control to their owner's hand.

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.

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}.

Swamp

Cogwork Assembler

{7}: Create a token that's a copy of target artifact. That token gains haste. Exile it at the beginning of the next end step.

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.

Glaring Fleshraker

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

Crashing Drawbridge

Defender
{T}: Creatures you control gain haste until end of turn.

Iron Myr

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 Retriever

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

Myr Enforcer

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

Symmetry Matrix

Whenever a creature with power equal to its toughness enters the battlefield under your control, you may pay {1}. If you do, draw a card.

Wake the Past

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

Thran Dynamo

Clock of Omens

Tap two untapped artifacts you control: Untap target artifact.

Counterspell

Lodestone Myr

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

Silver Myr

Myr Galvanizer

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

Scene of the Crime

Scene of the Crime enters the battlefield tapped.
{T}: Add {C}.
{T}, Tap an untapped creature you control: Add one mana of any color.
{2}, Sacrifice Scene of the Crime: Draw a card.

Myr Welder

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

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Buried Ruin: Return target artifact card from your graveyard to your hand.

Sol Ring

Myr Kinsmith

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

Myr Superion

Spend only mana produced by creatures to cast this spell.

Hovermyr

Blinkmoth Urn

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

Foundry Inspector

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

Genesis Chamber

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

Distant Melody

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

Plains

Shimmer Myr

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

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Herald's Horn

As Herald's Horn enters the battlefield, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Vanquisher's Banner

As Vanquisher's Banner enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Frogmyr Enforcer

Prototype {3}{R} — 2/2 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Steel Overseer

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

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.)

Reliquary Tower

Mountain

Myr Propagator

{3}, {T}: Create a token that's a copy of Myr Propagator.

Leaden Myr

Harvest Season

Search your library for up to X basic land cards, where X is the number of tapped creatures you control, put those cards onto the battlefield tapped, then shuffle.

Negate

Myr Sire

When Myr Sire dies, create a 1/1 colorless Phyrexian Myr artifact creature token.

Alloy Myr

Forest

Island

Sonic Screwdriver

{T}: Add one mana of any color.
{1}, {T}: Untap another target artifact.
{2}, {T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{3}, {T}: Target creature can't be blocked this turn.

Gold Myr

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Copper Myr

Arcane Signet

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

Spire of Industry

{T}: Add {C}.
{T}, Pay 1 life: Add one mana of any color. Activate only if you control an artifact.

Thoughtcast

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

Swords to Plowshares

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

Dispatch

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

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.

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.

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Myr Battlesphere

When Myr Battlesphere enters the battlefield, 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.

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.