Seat of the Synod

Ancient Den

All That Glitters

Enchant creature
Enchanted creature gets +1/+1 for each artifact and/or enchantment you control.

Chaos Wand

{4}, {T}: Target opponent exiles cards from the top of their library until they exile an instant or sorcery card. You may cast that card without paying its mana cost. Then put the exiled cards that weren't cast this way on the bottom of that library in a random order.

Everflowing Chalice

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

Assault Suit

Equipped creature gets +2/+2, has haste, can't attack you or planeswalkers you control, and can't be sacrificed.
At the beginning of each opponent's upkeep, you may have that player gain control of equipped creature until end of turn. If you do, untap it.
Equip {3}

Paradise Mantle

Equipped creature has "{T}: Add one mana of any color."
Equip {1}

Mishra's Bauble

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

Armillary Sphere

{2}, {T}, Sacrifice Armillary Sphere: Search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.

Amulet of Safekeeping

Whenever you become the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.
Creature tokens get -1/-0.

Tree of Tales

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Akroan Horse

Defender
When Akroan Horse enters, an opponent gains control of it.
At the beginning of your upkeep, each opponent creates a 1/1 white Soldier creature token.

Chief of the Foundry

Other artifact creatures you control get +1/+1.

Arcanist's Owl

Flying
When Arcanist's Owl enters, look at the top four cards of your library. You may reveal an artifact or enchantment card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Argentum Armor

Equipped creature gets +6/+6.
Whenever equipped creature attacks, destroy target permanent.
Equip {6}

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Blood Clock

At the beginning of each player's upkeep, that player returns a permanent they control to its owner's hand unless they pay 2 life.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Behemoth Sledge

Equipped creature gets +2/+2 and has trample and lifelink.
Equip {3}

Aeon Engine

Aeon Engine enters tapped.
{T}, Exile Aeon Engine: Reverse the game's turn order. (For example, if play had proceeded clockwise around the table, it now goes counterclockwise.)

Spellbook

Arcane Signet

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

Amareth, the Lustrous

Flying
Whenever another permanent you control enters, look at the top card of your library. If it shares a card type with that permanent, you may reveal that card and put it into your hand.

Dark Sphere

{T}, Sacrifice Dark Sphere: The next time a source of your choice would deal damage to you this turn, prevent half that damage, rounded down.

Bag of Holding

Whenever you discard a card, exile that card from your graveyard.
{2}, {T}: Draw a card, then discard a card.
{4}, {T}, Sacrifice Bag of Holding: Return all cards exiled with Bag of Holding to their owner's hand.

Angel of Invention

Flying, vigilance, lifelink
Fabricate 2 (When this creature enters, put two +1/+1 counters on it or create two 1/1 colorless Servo artifact creature tokens.)
Other creatures you control get +1/+1.

Angelheart Vial

Whenever you're dealt damage, you may put that many charge counters on Angelheart Vial.
{2}, {T}, Remove four charge counters from Angelheart Vial: You gain 2 life and draw a card.

Astral Cornucopia

Astral Cornucopia enters with X charge counters on it.
{T}: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.

Fountain of Youth

Aether Spellbomb

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

Darksteel Citadel

Captain's Claws

Equipped creature gets +1/+0.
Whenever equipped creature attacks, create a 1/1 white Kor Ally creature token that's tapped and attacking.
Equip {1}

Ancestral Blade

When Ancestral Blade enters, create a 1/1 white Soldier creature token, then attach Ancestral Blade to it.
Equipped creature gets +1/+1.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)