Sudden Substitution

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Exchange control of target noncreature spell and target creature. Then the spell's controller may choose new targets for it.

Aquatic Ingress

Up to two target creatures each get +1/+0 until end of turn and can't be blocked this turn. (Then exile this card. You may cast the creature later from exile.)

Sea Hag

When Sea Hag enters, creatures your opponents control get -4/-0 until end of turn.

Sea Hag // Aquatic Ingress

Engulf the Shore

Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.

Blue Sun's Zenith

Target player draws X cards. Shuffle Blue Sun's Zenith into its owner's library.

Whelming Wave

Return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.

Access Denied

Counter target spell. Create X 1/1 colorless Thopter artifact creature tokens with flying, where X is that spell's mana value.

Insidious Will

Choose one —
• Counter target spell.
• You may choose new targets for target spell.
• Copy target instant or sorcery spell. You may choose new targets for the copy.

Oona's Grace

Target player draws a card.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Discontinuity

During your turn, this spell costs {2}{U}{U} less to cast.
End the turn. (Exile all spells and abilities from the stack, including this card. The player whose turn it is discards down to their maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Petty Theft

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

Brazen Borrower

Flash
Flying
Brazen Borrower can block only creatures with flying.

Brazen Borrower // Petty Theft

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.

Ray of Command

Untap target creature an opponent controls and gain control of it until end of turn. That creature gains haste until end of turn. When you lose control of the creature, tap it.

Octavia, Living Thesis

This spell costs {8} less to cast if you have eight or more instant and/or sorcery cards in your graveyard.
Ward {8}
Magecraft — Whenever you cast or copy an instant or sorcery spell, target creature has base power and toughness 8/8 until end of turn.

Press the Enemy

Return target spell or nonland permanent an opponent controls to its owner's hand. You may cast an instant or sorcery spell with equal or lesser mana value from your hand without paying its mana cost.

Elminster's Simulacrum

For each opponent, you create a token that's a copy of up to one target creature that player controls.

Otterball Antics

Create a 1/1 blue and red Otter creature token with prowess. If this spell was cast from anywhere other than your hand, put a +1/+1 counter on that creature. (Whenever you cast a noncreature spell, a creature with prowess gets +1/+1 until end of turn.)
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Mystic Reflection

Choose target nonlegendary creature. The next time one or more creatures or planeswalkers enter this turn, they enter as copies of the chosen creature.
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.)

Eldrazi Confluence

Choose three. You may choose the same mode more than once.
• Target creature gets +3/-3 until end of turn.
• Exile target nonland permanent, then return it to the battlefield tapped under its owner's control.
• Create a 1/1 colorless Eldrazi Scion creature token with "Sacrifice this creature: Add {C}."

Bubble Up

Put target instant or sorcery card from your graveyard on top of your library. (Then exile this card. You may cast the creature later from exile.)

Aquatic Alchemist

Whenever you cast your first instant or sorcery spell each turn, Aquatic Alchemist gets +2/+0 until end of turn.

Aquatic Alchemist // Bubble Up

Rite of Undoing

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Return target nonland permanent you control and target nonland permanent you don't control to their owners' hands.

Desynchronization

Return each nonland permanent that's not historic to its owner's hand. (Artifacts, legendaries, and Sagas are historic.)

Sorcerous Squall

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Target opponent mills nine cards, then you may cast an instant or sorcery spell from that player's graveyard without paying its mana cost. If that spell would be put into a graveyard, exile it instead.

Reenact the Crime

Exile target nonland card in a graveyard that was put there from anywhere this turn. Copy it. You may cast the copy without paying its mana cost.

Faerie Slumber Party

Return all creatures to their owners' hands. For each opponent who controlled a creature returned this way, you create two 1/1 blue Faerie creature tokens with flying and "This creature can block only creatures with flying."

Trap the Trespassers

Secret council — Each player secretly votes for a creature you don't control, then those votes are revealed. For each creature with one or more votes, put that many stun counters on it, then tap it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Commence the Endgame

This spell can't be countered.
Draw two cards, then amass Zombies X, where X is the number of cards in your hand. (Put X +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)

Inscription of Insight

Kicker {2}{U}{U}
Choose one. If this spell was kicked, choose any number instead.
• Return up to two target creatures to their owners' hands.
• Scry 2, then draw two cards.
• Target player creates an X/X blue Illusion creature token, where X is the number of cards in their hand.

Slip Out the Back

Put a +1/+1 counter on target creature. It phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

Intrude on the Mind

Reveal the top five cards of your library and separate them into two piles. An opponent chooses one of those piles. Put that pile into your hand and the other into your graveyard. Create a 0/0 colorless Thopter artifact creature token with flying, then put a +1/+1 counter on it for each card put into your graveyard this way.

Set Adrift

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Put target nonland permanent on top of its owner's library.

Bribery

Search target opponent's library for a creature card and put that card onto the battlefield under your control. Then that player shuffles.

Zimone's Hypothesis

You may put a +1/+1 counter on a creature. Then choose odd or even. Return each creature with power of the chosen quality to its owner's hand. (Zero is even.)

Haunting Imitation

Each player reveals the top card of their library. For each creature card revealed this way, create a token that's a copy of that card, except it's 1/1, it's a Spirit in addition to its other types, and it has flying. If no creature cards were revealed this way, return Haunting Imitation to its owner's hand.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Glimpse of Freedom

Draw a card.
Escape—{2}{U}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Free the Fae

Mill four cards. Then put an instant, sorcery, or Faerie card from among the milled cards into your hand.

Picklock Prankster

Picklock Prankster // Free the Fae

Inaction Injunction

Detain target creature an opponent controls. (Until your next turn, that creature can't attack or block and its activated abilities can't be activated.)
Draw a card.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Spelltwine

Exile target instant or sorcery card from your graveyard and target instant or sorcery card from an opponent's graveyard. Copy those cards. Cast the copies if able without paying their mana costs. Exile Spelltwine.

Whispers of the Muse

Buyback {5} (You may pay an additional {5} as you cast this spell. If you do, put this card into your hand as it resolves.)
Draw a card.

Maximize Altitude

Target creature gets +1/+1 and gains flying until end of turn.
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.)

Release to the Wind

Exile target nonland permanent. For as long as that card remains exiled, its owner may cast it without paying its mana cost.

Notorious Throng

Prowl {5}{U} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Rogue.)
Create X 1/1 black Faerie Rogue creature tokens with flying, where X is the damage dealt to your opponents this turn. If this spell's prowl cost was paid, take an extra turn after this one.

Lagoon Breach

The owner of target attacking creature you don't control puts it on 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

Time Stop

End the turn. (Exile all spells and abilities from the stack, including this card. The player whose turn it is discards down to their maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Persistent Nightmare

Skulk (This creature can't be blocked by creatures with greater power.)
When Persistent Nightmare deals combat damage to a player, return it to its owner's hand.

Startled Awake

Target opponent mills thirteen cards.
{3}{U}{U}: Put Startled Awake from your graveyard onto the battlefield transformed. Activate only as a sorcery.

Startled Awake // Persistent Nightmare

Eldritch Immunity

Target creature you control gains protection from each color until end of turn.
Overload {4}{C} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Witness the Future

Target player shuffles up to four target cards from their graveyard into their library. You look at the top four cards of your library, then put one of those cards into your hand and the rest on the bottom of your library in a random order.

Acquire

Search target opponent's library for an artifact card and put that card onto the battlefield under your control. Then that player shuffles.

Snapback

You may exile a blue card from your hand rather than pay this spell's mana cost.
Return target creature to its owner's hand.

Crush of Tentacles

Surge {3}{U}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Return all nonland permanents to their owners' hands. If this spell's surge cost was paid, create an 8/8 blue Octopus creature token.

Perplexing Test

Choose one —
• Return all creature tokens to their owners' hands.
• Return all nontoken creatures to their owners' hands.

Change of Plans

Each of X target creatures you control connive. You may have any number of them phase out. (To have a creature connive, draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

Kozilek's Command

Choose two —
• Target player creates X 0/1 colorless Eldrazi Spawn creature tokens with "Sacrifice this creature: Add {C}."
• Target player scries X, then draws a card.
• Exile target creature with mana value X or less.
• Exile up to X target cards from graveyards.

Inundate

Return all nonblue creatures to their owners' hands.

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.)

Mystic Confluence

Choose three. You may choose the same mode more than once.
• Counter target spell unless its controller pays {3}.
• Return target creature to its owner's hand.
• Draw a card.

Flawless Forgery

Casualty 3 (As you cast this spell, you may sacrifice a creature with power 3 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Exile target instant or sorcery card from an opponent's graveyard. Copy that card. You may cast the copy without paying its mana cost.

Serpentine Curve

Create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it, where X is one plus the total number of instant and sorcery cards you own in exile and in your graveyard.

Polymorphist's Jest

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Spectral Deluge

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.
Foretell {1}{U}{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.)

Masterful Replication

Choose one —
• Create two 3/3 colorless Golem artifact creature tokens.
• Choose target artifact you control. Each other artifact you control becomes a copy of that artifact until end of turn.

Capsizing Wave

Return target creature to its owner's hand. (Then exile this card. You may cast the creature later from exile.)

Sword Coast Serpent

Sword Coast Serpent can't be blocked as long as you've cast a noncreature spell this turn.

Sword Coast Serpent // Capsizing Wave

Glamerdye

Change the text of target spell or permanent by replacing all instances of one color word with another.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)