Salivating Gremlins

Whenever an artifact you control enters, Salivating Gremlins gets +2/+0 and gains trample until end of turn.

Timber Gorge

Timber Gorge enters tapped.
{T}: Add {R} or {G}.

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.

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.

Goblin Arsonist

When Goblin Arsonist dies, you may have it deal 1 damage to any target.

Myr Galvanizer

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

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.

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.

Woodland Stream

Woodland Stream enters tapped.
{T}: Add {G} or {U}.

Foul Orchard

Foul Orchard enters tapped.
{T}: Add {B} or {G}.

Submerged Boneyard

Submerged Boneyard enters tapped.
{T}: Add {U} or {B}.

Highland Lake

Highland Lake enters tapped.
{T}: Add {U} or {R}.

Dark Ritual

Myr Welder

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

Lay Claim

Enchant permanent
You control enchanted permanent.
Cycling {2} ({2}, Discard this card: Draw a card.)

Perilous Myr

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

Unknown Shores

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Attrition

{B}, Sacrifice a creature: Destroy target nonblack creature.

Forest

Myr Landshaper

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

Sensei's Divining Top

{1}: Look at the top three cards of your library, then put them back in any order.
{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Scuttling Doom Engine

Scuttling Doom Engine can't be blocked by creatures with power 2 or less.
When Scuttling Doom Engine dies, it deals 6 damage to target opponent or planeswalker.

Lifecraft Awakening

Put X +1/+1 counters on target artifact you control. If it isn't a creature or Vehicle, it becomes a 0/0 Construct artifact creature.

Myr Incubator

{6}, {T}, Sacrifice Myr Incubator: Search your library for any number of artifact cards, exile them, then create that many 1/1 colorless Myr artifact creature tokens. Then shuffle.

Hovermyr

Swamp

Joiner Adept

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

Threaten

Untap target creature and gain control of it until end of turn. That creature gains haste until end of turn. (It can attack and {T} this turn.)

Mountain

Loam Larva

When Loam Larva enters, you may search your library for a basic land card, reveal it, then shuffle and put that card on top.

Evolving Wilds

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

Unwinding Clock

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

Cinder Barrens

Cinder Barrens enters tapped.
{T}: Add {B} or {R}.

Copy Artifact

You may have Copy Artifact enter as a copy of any artifact on the battlefield, except it's an enchantment in addition to its other types.

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.