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.)

Augury Raven

Flying
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Eel Umbra

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Mystic Sanctuary

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

Disenchant

Stop Cold

Flash
Enchant artifact or creature
When Stop Cold enters, tap enchanted permanent.
Enchanted permanent loses all abilities and doesn't untap during its controller's untap step.

Archaeomancer

When Archaeomancer enters, return target instant or sorcery card from your graveyard to your hand.

Judge's Familiar

Flying
Sacrifice Judge's Familiar: Counter target instant or sorcery spell unless its controller pays {1}.

Behold the Multiverse

Scry 2, then draw two cards.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Iron Verdict

Iron Verdict deals 5 damage to target tapped creature.
Foretell {W} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Doomskar Oracle

Whenever you cast your second spell each turn, you gain 2 life.
Foretell {W} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Benevolent Blessing

Flash
Enchant creature
As Benevolent Blessing enters, choose a color.
Enchanted creature has protection from the chosen color. This effect doesn't remove Auras and Equipment you control that are already attached to it.

Generous Gift

Destroy target permanent. Its controller creates a 3/3 green Elephant creature token.

Negate

Plains

Tamiyo's Compleation

Flash
Enchant artifact, creature, or planeswalker
When Tamiyo's Compleation enters, tap enchanted permanent. If it's an Equipment, unattach it.
Enchanted permanent loses all abilities and doesn't untap during its controller's untap step.

Utter Insignificance

Flash
Enchant creature
Enchanted creature loses all abilities and has base power and toughness 1/1.
{2}{C}: Exile enchanted creature.

Snap

Return target creature to its owner's hand. Untap up to two lands.

Mocking Sprite

Flying
Instant and sorcery spells you cast cost {1} less to cast.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Geyser Drake

Flying
During turns other than yours, spells you cast cost {1} less to cast.

Arcane Signet

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

Thought Vessel

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

Karfell Harbinger

{T}: Add {U}. Spend this mana only to foretell a card from your hand or cast an instant or sorcery spell.

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Starlit Mantle

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature you control
When Starlit Mantle enters, enchanted creature gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)
Enchanted creature gets +1/+1.

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Whitemane Lion

Flash
When Whitemane Lion enters, return a creature you control to its owner's hand.

Azorius Signet

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Impulse

Look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Phantom Interference

Spree (Choose one or more additional costs.)
+ {3} — Create a 2/2 white Spirit creature token with flying.
+ {1} — Counter target spell unless its controller pays {2}.

Hyena Umbra

Enchant creature
Enchanted creature gets +1/+1 and has first strike.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Lonely Arroyo

Lonely Arroyo enters tapped.
When Lonely Arroyo enters, it deals 1 damage to target opponent.
{T}: Add {W} or {U}.

Ethereal Armor

Enchant creature
Enchanted creature gets +1/+1 for each enchantment you control and has first strike.

Memory Lapse

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Holy Cow

Flash
Flying
When Holy Cow enters, you gain 2 life and scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Apostle's Blessing

({W/P} can be paid with either {W} or 2 life.)
Target artifact or creature you control gains protection from artifacts or from the color of your choice until end of turn.

Repulse

Return target creature to its owner's hand.
Draw a card.

Lawmage's Binding

Flash
Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.

Cathar Commando

Flash (You may cast this spell any time you could cast an instant.)
{1}, Sacrifice this creature: Destroy target artifact or enchantment.

Omen of the Sea

Flash (You may cast this spell any time you could cast an instant.)
When Omen of the Sea enters, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: 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.)

Moonsnare Prototype

{T}, Tap an untapped artifact or creature you control: Add {C}.
Channel — {4}{U}, Discard Moonsnare Prototype: The owner of target nonland permanent puts it on their choice of the top or bottom of their library.

Depart the Realm

Return target nonland permanent to its owner's hand.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Ravenform

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Mind Stone

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

Frantic Search

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

Resculpt

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

Island

Academy Wall

Defender
Whenever you cast an instant or sorcery spell, you may draw a card. If you do, discard a card. This ability triggers only once each turn.

Omen of the Sun

Flash
When Omen of the Sun enters, create two 1/1 white Human Soldier creature tokens and you gain 2 life.
{2}{W}, Sacrifice Omen of the Sun: Scry 2.

Naiad of Hidden Coves

During turns other than yours, spells you cast cost {1} less to cast.

Quick Study

Cradle of Safety

Flash
Enchant creature you control
When Cradle of Safety enters, enchanted creature gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)
Enchanted creature gets +1/+1.

Murmuring Mystic

Whenever you cast an instant or sorcery spell, create a 1/1 blue Bird Illusion creature token with flying.

Dog Umbra

Flash
Enchant creature
As long as another player controls enchanted creature, it can't attack or block. Otherwise, Dog Umbra has umbra armor. (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

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.

Brainstorm

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

Counterspell

Loan Shark

When Loan Shark enters, if you've cast two or more spells this turn, draw a card.
Plot {3}{U} (You may pay {3}{U} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Unwind

Counter target noncreature spell. Untap up to three lands.

Steel of the Godhead

Enchant creature
As long as enchanted creature is white, it gets +1/+1 and has lifelink. (Damage dealt by the creature also causes its controller to gain that much life.)
As long as enchanted creature is blue, it gets +1/+1 and can't be blocked.

Refute

Counter target spell. Draw a card, then discard a card.

Jem Lightfoote, Sky Explorer

Flying, vigilance
At the beginning of your end step, if you haven't cast a spell from your hand this turn, draw a card.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)