Seat of the Synod

Spellskite

{U/P}: Change a target of target spell or ability to Spellskite. ({U/P} can be paid with either {U} or 2 life.)

Thoughtcast

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

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Unwinding Clock

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

Ghirapur Aether Grid

Tap two untapped artifacts you control: Ghirapur Aether Grid deals 1 damage to any target.

Saheeli, Sublime Artificer

Whenever you cast a noncreature spell, create a 1/1 colorless Servo artifact creature token.
−2: Target artifact you control becomes a copy of another target artifact or creature you control until end of turn, except it's an artifact in addition to its other types.

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Darksteel Citadel

Jeweled Amulet

{1}, {T}: Put a charge counter on Jeweled Amulet. Note the type of mana spent to pay this activation cost. Activate only if there are no charge counters on Jeweled Amulet.
{T}, Remove a charge counter from Jeweled Amulet: Add one mana of Jeweled Amulet's last noted type.

Altar of the Brood

Whenever another permanent enters the battlefield under your control, each opponent mills a card.

Urza, Lord High Artificer

When Urza, Lord High Artificer enters the battlefield, create a 0/0 colorless Construct artifact creature token with "This creature gets +1/+1 for each artifact you control."
Tap an untapped artifact you control: Add {U}.
{5}: Shuffle your library, then exile the top card. Until end of turn, you may play that card without paying its mana cost.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Izzet Signet

Chrome Mox

Imprint — When Chrome Mox enters the battlefield, you may exile a nonartifact, nonland card from your hand.
{T}: Add one mana of any of the exiled card's colors.

Paradox Engine

Whenever you cast a spell, untap all nonland permanents you control.

City of Traitors

When you play another land, sacrifice City of Traitors.
{T}: Add {C}{C}.

Etherium Sculptor

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

Vandalblast

Destroy target artifact you don't control.
Overload {4}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Academy Ruins

{T}: Add {C}.
{1}{U}, {T}: Put target artifact card from your graveyard on top of your library.

Chief Engineer

Artifact spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting an artifact spell pays for {1} or one mana of that creature's color.)

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Fabricate

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

Tangle Wire

Fading 4 (This artifact enters the battlefield with four fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
At the beginning of each player's upkeep, that player taps an untapped artifact, creature, or land they control for each fade counter on Tangle Wire.

Sai, Master Thopterist

Whenever you cast an artifact spell, create a 1/1 colorless Thopter artifact creature token with flying.
{1}{U}, Sacrifice two artifacts: Draw a card.

Goblin Welder

{T}: Choose target artifact a player controls and target artifact card in that player's graveyard. If both targets are still legal as this ability resolves, that player simultaneously sacrifices the artifact and returns the artifact card to the battlefield.

Tomb of the Spirit Dragon

{T}: Add {C}.
{2}, {T}: You gain 1 life for each colorless creature you control.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Island

Myr Retriever

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

Grim Monolith

Grim Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{4}: Untap Grim Monolith.

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Krark-Clan Ironworks

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Clock of Omens

Tap two untapped artifacts you control: Untap target artifact.

Scrap Trawler

Whenever Scrap Trawler or another artifact you control is put into a graveyard from the battlefield, return to your hand target artifact card in your graveyard with lesser mana value.

Reckless Fireweaver

Whenever an artifact enters the battlefield under your control, Reckless Fireweaver deals 1 damage to each opponent.

Volcanic Island

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters the battlefield with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Command Tower

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

Smuggler's Copter

Flying
Whenever Smuggler's Copter attacks or blocks, you may draw a card. If you do, discard a card.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

Mox Amber

{T}: Add one mana of any color among legendary creatures and planeswalkers you control.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Whir of Invention

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

Pithing Needle

As Pithing Needle enters the battlefield, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Phyrexian Revoker

As Phyrexian Revoker enters the battlefield, choose a nonland card name.
Activated abilities of sources with the chosen name can't be activated.

Great Furnace

Mox Diamond

If Mox Diamond would enter the battlefield, you may discard a land card instead. If you do, put Mox Diamond onto the battlefield. If you don't, put it into its owner's graveyard.
{T}: Add one mana of any color.

Sulfur Falls

Sulfur Falls enters the battlefield tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Fellwar Stone

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

Mox Opal

Metalcraft — {T}: Add one mana of any color. Activate only if you control three or more artifacts.