Seat of the Synod

Lotus Petal

{T}, Sacrifice this artifact: Add one mana of any color.

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Memory Guardian

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

Pithing Needle

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

Thought Monitor

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When this creature enters, draw two cards.

Dismember

({B/P} can be paid with either {B} or 2 life.)
Target creature gets -5/-5 until end of turn.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Mishra's Bauble

{T}, Sacrifice this artifact: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Kappa Cannoneer

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Ward {4}
Whenever this creature or another artifact you control enters, put a +1/+1 counter on this creature. It can't be blocked this turn.

Soporific Springs

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {U}.

Sink into Stupor

Return target spell or nonland permanent an opponent controls to its owner's hand.

Sink into Stupor // Soporific Springs

Lavaspur Boots

Equipped creature gets +1/+0 and has haste and ward {1}. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)
Equip {1}

Urza's Bauble

{T}, Sacrifice this artifact: Look at a card at random in target player's hand. You draw a card at the beginning of the next turn's upkeep.

Mox Opal

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

Emry, Lurker of the Loch

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

Pinnacle Emissary

Whenever you cast an artifact spell, create a 1/1 colorless Drone artifact creature token with flying and "This token can block only creatures with flying."
Warp {U/R} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Tormod's Crypt

{T}, Sacrifice this artifact: Exile target player's graveyard.

Aether Spellbomb

{U}, Sacrifice this artifact: Return target creature to its owner's hand.
{1}, Sacrifice this artifact: Draw a card.

Shadowspear

Equipped creature gets +1/+1 and has trample and lifelink.
{1}: Permanents your opponents control lose hexproof and indestructible until end of turn.
Equip {2}

Island

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard this card: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Ancient Tomb

{T}: Add {C}{C}. This land deals 2 damage to you.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — This Saga gains "{T}: Add {C}."
II — This Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This token gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Thoughtcast

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