Sapphire Medallion

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

Emry, Lurker of the Loch

This spell costs {1} less to cast for each artifact you control.
When Emry, Lurker of the Loch enters, mill four cards.
{T}: Choose target artifact card in your graveyard. You may cast that card this turn. (You still pay its costs. Timing rules still apply.)

Arcane Signet

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

Mirran Spy

Flying
Whenever you cast an artifact spell, you may untap target creature.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Foundry Inspector

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

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Thought Vessel

Darksteel Citadel

Dramatic Reversal

Untap all nonland permanents you control.

Seat of the Synod

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Riddlesmith

Whenever you cast an artifact spell, you may draw a card. If you do, discard a card.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Shimmer Myr

Flash
You may cast artifact spells as though they had flash.

Counterspell

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.

Ornithopter

Codex Shredder

{T}: Target player mills a card. (They put the top card of their library into their graveyard.)
{5}, {T}, Sacrifice Codex Shredder: Return target card from your graveyard to your hand.

Archway of Innovation

Archway of Innovation enters tapped unless you control an Island.
{T}: Add {U}.
{U}, {T}: The next spell you cast this turn has improvise. (Your artifacts can help cast that spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Ponder

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

Kiora, the Rising Tide

When Kiora enters, draw two cards, then discard two cards.
Threshold — Whenever Kiora attacks, if there are seven or more cards in your graveyard, you may create Scion of the Deep, a legendary 8/8 blue Octopus creature token.

Padeem, Consul of Innovation

Artifacts you control have hexproof. (They can't be the targets of spells or abilities your opponents control.)
At the beginning of your upkeep, if you control the artifact with the highest mana value or tied for the highest mana value, draw a card.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Negate

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.