Geode Grotto

(Transforms from Dowsing Device.)
{T}: Add {R}.
{2}{R}, {T}: Until end of turn, target creature gains haste and gets +X/+0, where X is the number of artifacts you control. Activate only as a sorcery.

Dowsing Device

Whenever Dowsing Device or another artifact enters the battlefield under your control, up to one target creature you control gets +1/+0 and gains haste until end of turn. Then transform Dowsing Device if you control four or more artifacts.

Dowsing Device // Geode Grotto

Suntouched Myr

Sunburst (This enters the battlefield with a +1/+1 counter on it for each color of mana spent to cast it.)

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}.

Great Furnace

Brudiclad, Telchor Engineer

Creature tokens you control have haste.
At the beginning of combat on your turn, create a 2/1 blue Phyrexian Myr artifact creature token. Then you may choose a token you control. If you do, each other token you control becomes a copy of that token.

Rustvale Bridge

Rustvale Bridge enters the battlefield tapped.
Indestructible
{T}: Add {R} or {W}.

Urza's Incubator

As Urza's Incubator enters the battlefield, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Vault of Whispers

Mycosynth Golem

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Artifact creature spells you cast have affinity for artifacts. (They cost {1} less to cast for each artifact you control.)

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.

Alloy Myr

Myr Scrapling

Sacrifice Myr Scrapling: Put a +1/+1 counter on target creature.

Shrine of Loyal Legions

At the beginning of your upkeep or whenever you cast a white spell, put a charge counter on Shrine of Loyal Legions.
{3}, {T}, Sacrifice Shrine of Loyal Legions: Create a 1/1 colorless Phyrexian Myr artifact creature token for each charge counter on Shrine of Loyal Legions.

Myr Mindservant

Darksteel Citadel

Myrsmith

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

Plains

Thought Monitor

Affinity for artifacts
Flying
When Thought Monitor enters the battlefield, draw two cards.

Blinkmoth Infusion

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

Lodestone Myr

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

Gold Myr

Plated Onslaught

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Creatures you control get +2/+1 until end of turn.

Island

Thoughtcast

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

Myr Galvanizer

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

Master's Call

Create two 1/1 colorless Myr artifact creature tokens.

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.

Myr Enforcer

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

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.

Ancient Den

Mishra's Workshop

{T}: Add {C}{C}{C}. Spend this mana only to cast artifact spells.

Razortide Bridge

Razortide Bridge enters the battlefield tapped.
Indestructible
{T}: Add {W} or {U}.

Goldmire Bridge

Goldmire Bridge enters the battlefield tapped.
Indestructible
{T}: Add {W} or {B}.

Seat of the Synod

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.)

Tezzeret, Master of the Bridge

Creature and planeswalker spells you cast have affinity for artifacts. (They cost {1} less to cast for each artifact you control.)
+2: Tezzeret, Master of the Bridge deals X damage to each opponent, where X is the number of artifacts you control. You gain X life.
−3: Return target artifact card from your graveyard to your hand.
−8: Exile the top ten cards of your library. Put all artifact cards from among them onto the battlefield.

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.

Mistvault Bridge

Mistvault Bridge enters the battlefield tapped.
Indestructible
{T}: Add {U} or {B}.

Myr Moonvessel

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.

Vault of Catlacan

(Transforms from Storm the Vault.)
{T}: Add one mana of any color.
{T}: Add {U} for each artifact you control.

Storm the Vault

Whenever one or more creatures you control deal combat damage to a player, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
At the beginning of your end step, if you control five or more artifacts, transform Storm the Vault.

Storm the Vault // Vault of Catlacan

Parcel Myr

Mirrodin Besieged

As Mirrodin Besieged enters the battlefield, 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.

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.

Shimmer Myr

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

Leaden Myr

Barracks of the Thousand

(Transforms from Thousand Moons Smithy.)
{T}: Add {W}.
Whenever you cast an artifact or creature spell using mana produced by Barracks of the Thousand, create a white Gnome Soldier artifact creature token with "This creature's power and toughness are each equal to the number of artifacts and/or creatures you control."

Thousand Moons Smithy

When Thousand Moons Smithy enters the battlefield, create a white Gnome Soldier artifact creature token with "This creature's power and toughness are each equal to the number of artifacts and/or creatures you control."
At the beginning of your precombat main phase, you may tap five untapped artifacts and/or creatures you control. If you do, transform Thousand Moons Smithy.

Thousand Moons Smithy // Barracks of the Thousand

Iron Myr

Myr Propagator

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

Knighted Myr

{2}{W}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Knighted Myr, it gains double strike until end of turn.

Omega Myr

Myr Superion

Spend only mana produced by creatures to cast this spell.

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Myr Retriever

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

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.

Mountain

Open the Vaults

Return all artifact and enchantment cards from all graveyards to the battlefield under their owners' control. (Auras with nothing to enchant remain in graveyards.)

Inventors' Fair

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
{T}: Add {C}.
{4}, {T}, Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

Brilliant Restoration

Return all artifact and enchantment cards from your graveyard to the battlefield.

Power Depot

Power Depot enters the battlefield tapped.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast artifact spells or activate abilities of artifacts.
Modular 1

Alpha Myr

Perilous Myr

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

Hovermyr

Tecutlan, the Searing Rift

(Transforms from Brass's Tunnel-Grinder.)
{T}: Add {R}.
Whenever you cast a permanent spell using mana produced by Tecutlan, the Searing Rift, discover X, where X is that spell's mana value.

Brass's Tunnel-Grinder

When Brass's Tunnel-Grinder enters the battlefield, discard any number of cards, then draw that many cards plus one.
At the beginning of your end step, if you descended this turn, put a bore counter on Brass's Tunnel-Grinder. Then if there are three or more bore counters on it, remove those counters and transform it. (You descended if a permanent card was put into your graveyard from anywhere.)

Brass's Tunnel-Grinder // Tecutlan, the Searing Rift

Myr Quadropod

{3}: Switch Myr Quadropod's power and toughness until end of turn.

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.

Swamp

Myr Landshaper

{T}: Target land becomes an artifact in addition to its other types until end of turn.

Drossforge Bridge

Drossforge Bridge enters the battlefield tapped.
Indestructible
{T}: Add {B} or {R}.

Myr Welder

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

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.

Reflections of Littjara

As Reflections of Littjara enters the battlefield, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Silver Myr

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.

Palladium Myr

Door of Destinies

As Door of Destinies enters the battlefield, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.
Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.

Coretapper

{T}: Put a charge counter on target artifact.
Sacrifice Coretapper: Put two charge counters on target artifact.

Sarcomite Myr

{2}: Sarcomite Myr gains flying until end of turn.
{2}, Sacrifice Sarcomite Myr: Draw a card.

Copper Myr

Glimmervoid

At the beginning of the end step, if you control no artifacts, sacrifice Glimmervoid.
{T}: Add one mana of any color.

Myr Sire

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

Cloud Key

As Cloud Key enters the battlefield, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Silverbluff Bridge

Silverbluff Bridge enters the battlefield tapped.
Indestructible
{T}: Add {U} or {R}.

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.)