Saiba Trespassers

Channel — {3}{U}, Discard Saiba Trespassers: Tap up to two target creatures you don't control. Those creatures don't untap during their controller's next untap step.

Network Terminal

{T}: Add one mana of any color.
{1}, {T}, Tap another untapped artifact you control: Draw a card, then discard a card.

Sojourner's Companion

Affinity for artifacts
Artifact landcycling {2} ({2}, Discard this card: Search your library for an artifact land card, reveal it, put it into your hand, then shuffle.)

Stern Lesson

Draw two cards, then discard a card. Create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Mind Stone

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

Mnemonic Sphere

{1}{U}, Sacrifice Mnemonic Sphere: Draw two cards.
Channel — {U}, Discard Mnemonic Sphere: Draw a card.

Thoughtcast

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

Etherium Sculptor

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

Seat of the Synod

Foundry Inspector

Maelstrom Colossus

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)

Counterspell

Arcane Signet

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

Staunch Throneguard

Vigilance
When Staunch Throneguard enters the battlefield, you become the monarch.

Shrine Steward

When Shrine Steward enters the battlefield, you may search your library for an Aura or Shrine card, reveal it, put it into your hand, then shuffle.

Bonder's Ornament

{T}: Add one mana of any color.
{4}, {T}: Each player who controls a permanent named Bonder's Ornament draws a card.

Urza, Powerstone Prodigy

Vigilance
{1}, {T}: Draw a card, then discard a card.
Whenever you discard one or more artifact cards, create a tapped Powerstone token. This ability triggers only once each turn. (The token is an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Fall from Favor

Enchant creature
When Fall from Favor enters the battlefield, tap enchanted creature and you become the monarch.
Enchanted creature doesn't untap during its controller's untap step unless that player is the monarch.

Fractured Powerstone

{T}: Add {C}.
{T}: Roll the planar die. Activate only as a sorcery.

Disruption Protocol

As an additional cost to cast this spell, tap an untapped artifact you control or pay {1}.
Counter target spell.

Myr Enforcer

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

Freed from the Real

Enchant creature
{U}: Tap enchanted creature.
{U}: Untap enchanted creature.

Mirrorshell Crab

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
Channel — {2}{U}, Discard Mirrorshell Crab: Counter target spell or ability unless its controller pays {3}.

Fellwar Stone

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

Spire Golem

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