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.

Arcbound Crusher

Trample
Whenever another artifact enters, put a +1/+1 counter on Arcbound Crusher.
Modular 1 (This creature enters with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Thirst for Knowledge

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

Copper Myr

Vedalken Engineer

{T}: Add two mana of any one color. Spend this mana only to cast artifact spells or activate abilities of artifacts.

Silver Myr

Loxodon Warhammer

Equipped creature gets +3/+0 and has trample and lifelink.
Equip {3}

Plains

Gold Myr

Island

Swamp

Seat of the Synod

Cranial Plating

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

Pentad Prism

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
Remove a charge counter from Pentad Prism: Add one mana of any color.

Broodstar

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
Broodstar's power and toughness are each equal to the number of artifacts you control.

Etched Oracle

Sunburst (This enters with a +1/+1 counter on it for each color of mana spent to cast it.)
{1}, Remove four +1/+1 counters from Etched Oracle: Target player draws three cards.

Ancient Den

Serum Tank

Whenever Serum Tank or another artifact enters, put a charge counter on Serum Tank.
{3}, {T}, Remove a charge counter from Serum Tank: Draw a card.

Keep Watch

Whiplash Trap

If an opponent had two or more creatures enter the battlefield under their control this turn, you may pay {U} rather than pay this spell's mana cost.
Return two target creatures to their owners' hands.

Sludge Strider

Whenever another artifact you control enters or leaves the battlefield, you may pay {1}. If you do, target player loses 1 life and you gain 1 life.

Forest

Mountain

Skeleton Shard

{3}, {T} or {B}, {T}: Return target artifact creature card from your graveyard to your hand.

Iron Myr

Fabricate

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

Arsenal Thresher

As Arsenal Thresher enters, you may reveal any number of other artifact cards from your hand. Arsenal Thresher enters with a +1/+1 counter on it for each card revealed this way.

Darksteel Forge

Artifacts you control have indestructible. (Effects that say "destroy" don't destroy them. Artifact creatures with indestructible can't be destroyed by damage.)

Qumulox

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

Tree of Tales

Bosh, Iron Golem

Trample
{3}{R}, Sacrifice an artifact: Bosh, Iron Golem deals damage equal to the sacrificed artifact's mana value to any target.

Nuisance Engine

{2}, {T}: Create a 0/1 colorless Pest artifact creature token.

Suntouched Myr

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

Lodestone Myr

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

Arcbound Slith

Whenever Arcbound Slith deals combat damage to a player, put a +1/+1 counter on it.
Modular 1 (This creature enters with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Leaden Myr

Vault of Whispers

Myr Enforcer

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

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.

Great Furnace

Wizard Replica

Flying
{U}, Sacrifice Wizard Replica: Counter target spell unless its controller pays {2}.

Sarcomite Myr

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

Pentavus

Pentavus enters with five +1/+1 counters on it.
{1}, Remove a +1/+1 counter from Pentavus: Create a 1/1 colorless Pentavite artifact creature token with flying.
{1}, Sacrifice a Pentavite: Put a +1/+1 counter on Pentavus.