Seat of the Synod

Esper Battlemage

{W}, {T}: Prevent the next 2 damage that would be dealt to you this turn.
{B}, {T}: Target creature gets -1/-1 until end of turn.

Glimmervoid

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

Etched Champion

Metalcraft — Etched Champion has protection from each color as long as you control three or more artifacts.

Vault of Whispers

Ethersworn Canonist

Each player who has cast a nonartifact spell this turn can't cast additional nonartifact spells.

Snapsail Glider

Metalcraft — Snapsail Glider has flying as long as you control three or more artifacts.

Stoic Rebuttal

Metalcraft — This spell costs {1} less to cast if you control three or more artifacts.
Counter target spell.

Etherium Sculptor

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

Ponder

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

Skycloud Expanse

Darksteel Citadel

Razorfield Rhino

Metalcraft — Razorfield Rhino gets +2/+2 as long as you control three or more artifacts.

Tezzeret the Seeker

+1: Untap up to two target artifacts.
−X: Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.
−5: Artifacts you control become artifact creatures with base power and toughness 5/5 until end of turn.

Ethersworn Shieldmage

Flash
When Ethersworn Shieldmage enters, prevent all damage that would be dealt to artifact creatures this turn.

Chrome Steed

Metalcraft — Chrome Steed gets +2/+2 as long as you control three or more artifacts.

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.

Tezzeret's Touch

Enchant artifact
Enchanted artifact is a creature with base power and toughness 5/5 in addition to its other types.
When enchanted artifact is put into a graveyard, return that card to its owner's hand.

Tempered Steel

Artifact creatures you control get +2/+2.

Esper Charm

Choose one —
• Destroy target enchantment.
• Draw two cards.
• Target player discards two cards.

Darkwater Catacombs

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.

Ancient Den

Dispatch

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

Arcane Sanctum

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

Esper Sojourners

When you cycle Esper Sojourners or it dies, you may tap or untap target permanent.
Cycling {2}{U} ({2}{U}, Discard this card: Draw a card.)