Crumbling Necropolis

Crumbling Necropolis enters tapped.
{T}: Add {U}, {B}, or {R}.

Have

Myrsmith

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

Artificer Class

(Gain the next level as a sorcery to add its ability.)
The first artifact spell you cast each turn costs {1} less to cast.
{1}{U}: Level 2
When this Class becomes level 2, reveal cards from the top of your library until you reveal an artifact card. Put that card into your hand and the rest on the bottom of your library in a random order.
{5}{U}: Level 3
At the beginning of your end step, create a token that's a copy of target artifact you control.

Myr Superion

Spend only mana produced by creatures to cast this spell.

Swords to Plowshares

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

Plains

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.

Exotic Orchard

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

Sarcomite Myr

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

Dispatch

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

Unwinding Clock

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

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.

Leaden Myr

Lodestone Myr

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

Mirrorworks

Whenever another nontoken artifact you control enters, you may pay {2}. If you do, create a token that's a copy of that artifact.

Bloodline Pretender

Changeling (This card is every creature type.)
As Bloodline Pretender enters, choose a creature type.
Whenever another creature you control of the chosen type enters, put a +1/+1 counter on Bloodline Pretender.

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.

Dimir Signet

Myr Propagator

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

One with the Machine

Draw cards equal to the highest mana value among artifacts you control.

Cranial Plating

Equipped creature gets +1/+0 for each artifact you control.
{B}{B}: Attach Cranial Plating to target creature you control.
Equip {1}

Myr Custodian

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

Arcane Sanctum

Arcane Sanctum enters tapped.
{T}: Add {W}, {U}, or {B}.

Darksteel Citadel

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Chromatic Lantern

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

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.

Thoughtcast

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

Path of Ancestry

Path of Ancestry enters 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.)

Shimmer Myr

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

Myr Welder

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

Gold Myr

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 Retriever

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

Song of Freyalise

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Until your next turn, creatures you control gain "{T}: Add one mana of any color."
III — Put a +1/+1 counter on each creature you control. Those creatures gain vigilance, trample, and indestructible until end of turn.

Bronze Guardian

Double strike
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Other artifacts you control have ward {2}.
Bronze Guardian's power is equal to the number of artifacts you control.

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}.

Darksteel Juggernaut

Indestructible
Darksteel Juggernaut's power and toughness are each equal to the number of artifacts you control.
Darksteel Juggernaut attacks each combat if able.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Parcel Myr

Solemn Simulacrum

When Solemn Simulacrum enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When Solemn Simulacrum dies, you may draw a card.

Myr Quadropod

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

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

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.

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.)

Swamp

Savage Lands

Savage Lands enters tapped.
{T}: Add {B}, {R}, or {G}.

Coretapper

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

Thought Monitor

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When Thought Monitor enters, draw two cards.

Tempered Steel

Artifact creatures you control get +2/+2.

Dance of the Manse

Return up to X target artifact and/or non-Aura enchantment cards each with mana value X or less from your graveyard to the battlefield. If X is 6 or more, those permanents are 4/4 creatures in addition to their other types.

Master of Etherium

Master of Etherium's power and toughness are each equal to the number of artifacts you control.
Other artifact creatures you control get +1/+1.

Palladium Myr

Myr Sire

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

Coalition Relic

{T}: Add one mana of any color.
{T}: Put a charge counter on Coalition Relic.
At the beginning of your first main phase, remove all charge counters from Coalition Relic. Add one mana of any color for each charge counter removed this way.

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.

Hovermyr

Island

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."

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Mystic Monastery

Mystic Monastery enters tapped.
{T}: Add {U}, {R}, or {W}.

Iron Myr

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.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Teshar, Ancestor's Apostle

Flying
Whenever you cast a historic spell, return target creature card with mana value 3 or less from your graveyard to the battlefield. (Artifacts, legendaries, and Sagas are historic.)

Alloy Myr

Foundry Inspector

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

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.

Etherium Sculptor

Mountain

Myr Enforcer

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

Bringer of the White Dawn

You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost.
Trample
At the beginning of your upkeep, you may return target artifact card from your graveyard to 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.

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.

Arcane Signet

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

Command Tower

Myr Scrapling

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

Azorius Signet

Forest

Sol Ring

Silver Myr

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.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

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.

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.)

Azorius Chancery

Azorius Chancery enters tapped.
When Azorius Chancery enters, return a land you control to its owner's hand.
{T}: Add {W}{U}.

Myr Galvanizer

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

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Orzhov Signet

Enthusiastic Mechanaut

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

Copper Myr

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.