Dream Halls

Rather than pay the mana cost for a spell, its controller may discard a card that shares a color with that spell.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Sakashima of a Thousand Faces

You may have Sakashima enter as a copy of another creature you control, except it has Sakashima's other abilities.
The "legend rule" doesn't apply to permanents you control.
Partner (You can have two commanders if both have partner.)

Trinket Mage

When this creature enters, you may search your library for an artifact card with mana value 1 or less, reveal that card, put it into your hand, then shuffle.

Season of Weaving

Choose up to five {P} worth of modes. You may choose the same mode more than once.
{P} — Draw a card.
{P}{P} — Choose an artifact or creature you control. Create a token that's a copy of it.
{P}{P}{P} — Return each nonland, nontoken permanent to its owner's hand.

Sculpting Steel

You may have this artifact enter as a copy of any artifact on the battlefield.

Sphinx of Forgotten Lore

Flash (You may cast this spell any time you could cast an instant.)
Flying
Whenever this creature attacks, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to that card's mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Conundrum Sphinx

Flying
Whenever this creature attacks, each player chooses a card name. Then each player reveals the top card of their library. If the card a player revealed has the name they chose, that player puts it into their hand. If it doesn't, that player puts it on the bottom of their library.

Sol Ring

Scholar of the Lost Trove

Flying
When this creature enters, you may cast target instant, sorcery, or artifact card from your graveyard without paying its mana cost. If an instant or sorcery spell cast this way would be put into your graveyard, exile it instead.

Counterspell

Raise the Palisade

Choose a creature type. Return all creatures that aren't of the chosen type to their owners' hands.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Cloudreader Sphinx

Flying
When this creature enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Sphinx of Foresight

You may reveal this card from your opening hand. If you do, scry 3 at the beginning of your first upkeep.
Flying
At the beginning of your upkeep, scry 1.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Curator of Mysteries

Flying
Whenever you cycle or discard another card, scry 1.
Cycling {U} ({U}, Discard this card: Draw a card.)

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Wash Out

Return all permanents of the color of your choice to their owners' hands.

Gauntlet of Power

As this artifact enters, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

Arcane Signet

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

Dazzling Sphinx

Flying
Whenever this creature deals combat damage to a player, that player 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 that player puts the exiled cards that weren't cast this way on the bottom of their library in a random order.

Phyrexian Metamorph

({U/P} can be paid with either {U} or 2 life.)
You may have this creature enter as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.

Misty Rainforest

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Maze of Ith

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Pact of Negation

Counter target spell.
At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.

Snow-Covered Island

Fabricate

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

Marauding Sphinx

Flying, vigilance, ward {2}
Whenever you commit a crime, surveil 2. This ability triggers only once each turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

Sphinx of Clear Skies

Flying, ward {2}
Domain — Whenever this creature deals combat damage to a player, reveal the top X cards of your library, where X is the number of basic land types among lands you control. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard. (Piles can be empty.)

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.")

Jwari Ruins

Jwari Disruption

Counter target spell unless its controller pays {1}.

Jwari Disruption // Jwari Ruins

Master of Winds

Flying
When this creature enters, draw two cards, then discard a card.
Whenever you cast an instant, sorcery, or Wizard spell, you may have this creature's base power and toughness become 4/1 or 1/4 until end of turn.

Unesh, Criosphinx Sovereign

Flying
Sphinx spells you cast cost {2} less to cast.
Whenever Unesh or another Sphinx you control enters, reveal the top four cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Reliquary Tower

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

Thran Dynamo

Clever Impersonator

You may have this creature enter as a copy of any nonland permanent on the battlefield.

Sea Gate, Reborn

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

Sea Gate Restoration

Draw cards equal to the number of cards in your hand plus one. You have no maximum hand size for the rest of the game.

Sea Gate Restoration // Sea Gate, Reborn

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Scalding Tarn

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Argent Sphinx

Flying
Metalcraft — {U}: Exile this creature. Return it to the battlefield under your control at the beginning of the next end step. Activate only if you control three or more artifacts.

Urza's Incubator

As this artifact enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Enigma Thief

Prowl {3}{U} (You may cast this spell for its prowl cost if you dealt combat damage to a player this turn with a Sphinx or Rogue.)
Flying
When this creature enters, for each opponent, return up to one target nonland permanent that player controls to its owner's hand.

Flooded Strand

{T}, Pay 1 life, Sacrifice this land: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Vedalken Shackles

You may choose not to untap this artifact during your untap step.
{2}, {T}: Gain control of target creature with power less than or equal to the number of Islands you control for as long as this artifact remains tapped.

Universal Automaton

Changeling (This card is every creature type.)

Bloodline Pretender

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
Whenever another creature you control of the chosen type enters, put a +1/+1 counter on this creature.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Spark Double

You may have this creature enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Ancient Tomb

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

Rescuer Sphinx

Flying
As this creature enters, you may return a nonland permanent you control to its owner's hand. If you do, this creature enters with a +1/+1 counter on it.

Roaming Throne

Ward {2}
As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Extraplanar Lens

Imprint — When this artifact enters, you may exile target land you control.
Whenever a land with the same name as the exiled card is tapped for mana, its controller adds one mana of any type that land produced.

Polluted Delta

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Muddle the Mixture

Counter target instant or sorcery spell.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Caged Sun

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Consecrated Sphinx

Flying
Whenever an opponent draws a card, you may draw two cards.

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Sapphire Medallion

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

Mirrormade

You may have this enchantment enter as a copy of any artifact or enchantment on the battlefield.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Copy Artifact

You may have this enchantment enter as a copy of any artifact on the battlefield, except it's an enchantment in addition to its other types.

Soporific Springs

Sink into Stupor

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

Sink into Stupor // Soporific Springs

Scourge of Fleets

When this creature enters, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

Negate

Fellwar Stone

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

Witness of Tomorrows

Guardian of Tazeem

Flying
Landfall — Whenever a land you control enters, tap target creature an opponent controls. If that land is an Island, that creature doesn't untap during its controller's next untap step.

Dream Eater

Flash
Flying
When this creature enters, surveil 4. When you do, you may return target nonland permanent an opponent controls to its owner's hand. (To surveil 4, look at the top four cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Master of Predicaments

Flying
Whenever this creature deals combat damage to a player, choose a card in your hand. That player guesses whether the card's mana value is greater than 4. If the player guessed wrong, you may cast the card without paying its mana cost.

Displacer Kitten

Avoidance — Whenever you cast a noncreature spell, exile up to one target nonland permanent you control, then return that card to the battlefield under its owner's control.

Thought Vessel

Defiler of Dreams

Flying
As an additional cost to cast blue permanent spells, you may pay 2 life. Those spells cost {U} less to cast if you paid life this way. This effect reduces only the amount of blue mana you pay.
Whenever you cast a blue permanent spell, draw a card.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)