Retraction Helix

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

Mountain

Reckless Fireweaver

Whenever an artifact you control enters, Reckless Fireweaver deals 1 damage to each opponent.

Etherium Sculptor

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

Myr Enforcer

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

Galvanic Blast

Galvanic Blast deals 2 damage to any target.
Metalcraft — Galvanic Blast deals 4 damage instead if you control three or more artifacts.

Cleansing Wildfire

Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.
Draw a card.

Island

Steelfin Whale

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Whenever an artifact you control enters, untap Steelfin Whale.

Silverbluff Bridge

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

Darksteel Citadel

Frogmite

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Thoughtcast

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

Chromatic Sphere

{1}, {T}, Sacrifice Chromatic Sphere: Add one mana of any color. Draw a card.

Drafna's Restoration

Put any number of target artifact cards from target player's graveyard on top of their library in any order.

Banishing Knack

Chromatic Star

{1}, {T}, Sacrifice Chromatic Star: Add one mana of any color.
When Chromatic Star is put into a graveyard from the battlefield, draw a card.