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}.

Dreamtide Whale

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a player casts their second spell each turn, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Day's Undoing

Each player shuffles their hand and graveyard into their library, then draws seven cards. If it's your turn, end the turn. (Exile all spells and abilities from the stack, including this card. Discard down to your maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Majestic Metamorphosis

Until end of turn, target artifact or creature becomes a 4/4 Angel artifact creature and gains flying.
Draw a card.

Stormsurge Kraken

Hexproof
Lieutenant — As long as you control your commander, Stormsurge Kraken gets +2/+2 and has "Whenever Stormsurge Kraken becomes blocked, you may draw two cards."

Lightshell Duo

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When this creature enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Seize the Secrets

This spell costs {1} less to cast if you've committed a crime this turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)
Draw two cards.

The Magic Mirror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
You have no maximum hand size.
At the beginning of your upkeep, put a knowledge counter on The Magic Mirror, then draw a card for each knowledge counter on The Magic Mirror.

Mind Spiral

Gift a tapped Fish (You may promise an opponent a gift as you cast this spell. If you do, they create a tapped 1/1 blue Fish creature token before its other effects.)
Target player draws three cards. If the gift was promised, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Spellgyre

Choose one —
• Counter target spell.
• Surveil 2, then draw two cards. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Sinister Sabotage

Counter target spell.
Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Marauding Brinefang

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Dazzling Denial

Counter target spell unless its controller pays {2}. If you control a Bird, counter that spell unless its controller pays {4} instead.

Frantic Search

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

Fleeting Reflection

Target creature you control gains hexproof until end of turn. Untap that creature. Until end of turn, it becomes a copy of up to one other target creature.

Sapphire Medallion

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

Kitesail Larcenist

Flying, ward {1}
When Kitesail Larcenist enters, for each player, choose up to one other target artifact or creature that player controls. For as long as Kitesail Larcenist remains on the battlefield, the chosen permanents become Treasure artifacts with "{T}, Sacrifice this artifact: Add one mana of any color" and lose all other abilities.

Negate

Daring Waverider

When Daring Waverider enters, you may cast target instant or sorcery card with mana value 4 or less from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Shore Up

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Compulsive Research

Target player draws three cards. Then that player discards two cards unless they discard a land card.

Resculpt

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

Sol Ring

Commandeer

You may exile two blue cards from your hand rather than pay this spell's mana cost.
Gain control of target noncreature spell. You may choose new targets for it. (If that spell is an artifact, enchantment, or planeswalker, the permanent enters under your control.)

Petrifying Meddler

Devoid (This card has no color.)
When you cast this spell, tap up to one target creature and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Reach

Angler Turtle

Hexproof
Creatures your opponents control attack each combat if able.

Island

Murder of Crows

Flying
Whenever another creature dies, you may draw a card. If you do, discard a card.

Sphinx of Enlightenment

Flying
When Sphinx of Enlightenment enters, target opponent draws a card and you draw three cards.

Counterspell

Eluge, the Shoreless Sea

Eluge's power and toughness are each equal to the number of Islands you control.
Whenever Eluge enters or attacks, put a flood counter on target land. It's an Island in addition to its other types for as long as it has a flood counter on it.
The first instant or sorcery spell you cast each turn costs {U} (or {1}) less to cast for each land you control with a flood counter on it.

Thryx, the Sudden Storm

Flash (You may cast this spell any time you could cast an instant.)
Flying
Spells you cast with mana value 5 or greater cost {1} less to cast and can't be countered.

Tidespout Tyrant

Flying
Whenever you cast a spell, return target permanent to its owner's hand.

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Rowdy Research

This spell costs {1} less to cast for each creature that attacked this turn.
Draw three cards.

Drownyard Lurker

Vigilance
When you cast or cycle Drownyard Lurker, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this creature: Add {C}."
Cycling {2}{U} ({2}{U}, Discard this card: Draw a card.)

Keymaster Rogue

Keymaster Rogue can't be blocked.
When Keymaster Rogue enters, return a creature you control to its owner's hand.

Radical Idea

Draw a card.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Inspired Sphinx

Flying
When Inspired Sphinx enters, draw cards equal to the number of opponents you have.
{3}{U}: Create a 1/1 colorless Thopter artifact creature token with flying.

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.)

Shifting Grift

Spree (Choose one or more additional costs.)
+ {2} — Exchange control of two target creatures.
+ {1} — Exchange control of two target artifacts.
+ {1} — Exchange control of two target enchantments.

Cerulean Sphinx

Flying
{U}: Cerulean Sphinx's owner shuffles it into their library.

Dissolve

Counter target spell. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Archive Trap

If an opponent searched their library this turn, you may pay {0} rather than pay this spell's mana cost.
Target opponent mills thirteen cards.

Diluvian Primordial

Flying
When Diluvian Primordial enters, for each opponent, you may cast up to one target instant or sorcery card from that player's graveyard without paying its mana cost. If a spell cast this way would be put into a graveyard, exile it instead.

Aether Gale

Return six target nonland permanents to their owners' hands.

Repulse

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

Spell Swindle

Counter target spell. Create X Treasure tokens, where X is that spell's mana value. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Helium Squirter

Graft 3 (This creature enters with three +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)
{1}: Target creature with a +1/+1 counter on it gains flying until end of turn.

Windreader Sphinx

Flying
Whenever a creature with flying attacks, you may draw a card.

Long River's Pull

Gift a card (You may promise an opponent a gift as you cast this spell. If you do, they draw a card before its other effects.)
Counter target creature spell. If the gift was promised, instead counter target spell.

Gilded Lotus

Archive Dragon

Flying
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When Archive Dragon enters, scry 2.

Hurl into History

Counter target artifact or creature spell. Discover X, where X is that spell's mana value. (Exile cards from the top of your library until you exile a nonland card with that mana value or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Pearl of Wisdom

This spell costs {1} less to cast if you control an Otter.
Draw two cards.

Lagoon Breach

The owner of target attacking creature you don't control puts it on their choice of the top or bottom of their library.

Horned Loch-Whale

Flash
Ward {2}
Horned Loch-Whale enters tapped unless it's your turn.

Horned Loch-Whale // Lagoon Breach

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Unfathomable Truths

Devoid (This card has no color.)
Draw three cards and create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this creature: Add {C}."

Out of Air

This spell costs {2} less to cast if it targets a creature spell.
Counter target spell.

Skyskipper Duo

Flying
When Skyskipper Duo enters, exile up to one other target creature you control. Return it to the battlefield under its owner's control at the beginning of the next end step.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Shipwreck Dowser

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When this creature enters, return target instant or sorcery card from your graveyard to your hand.

Essence Scatter

Tolarian Terror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)