Curse of Echoes

Enchant player
Whenever enchanted player casts an instant or sorcery spell, each other player may copy that spell and may choose new targets for the copy they control.

Wistful Thinking

Target player draws two cards, then discards four cards.

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Boomerang

Return target permanent to its owner's hand.

Dreadwaters

Target player mills X cards, where X is the number of lands you control.

Run Away Together

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

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.)

Cephalid Broker

{T}: Target player draws two cards, then discards two cards.

Dampen Thought

Target player mills four cards.
Splice onto Arcane {1}{U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Island

Sands of Delirium

Aven Windreader

Flying (This creature can't be blocked except by creatures with flying or reach.)
{1}{U}: Target player reveals the top card of their library.

Cephalid Looter

{T}: Target player draws a card, then discards a card.

Polymorph

Destroy target creature. It can't be regenerated. Its controller reveals cards from the top of their library until they reveal a creature card. The player puts that card onto the battlefield, then shuffles all other cards revealed this way into their library.

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.

Sol Ring

Reckless Scholar

Unsummon

Return target creature to its owner's hand.

Bloodthirsty Blade

Equipped creature gets +2/+0 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
{1}: Attach Bloodthirsty Blade to target creature an opponent controls. Activate only as a sorcery.

Blue Sun's Zenith

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

Amphin Mutineer

When Amphin Mutineer enters, exile up to one target non-Salamander creature. That creature's controller creates a 4/3 blue Salamander Warrior creature token.
Encore {4}{U}{U} ({4}{U}{U}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Court of Cunning

When Court of Cunning enters, you become the monarch.
At the beginning of your upkeep, any number of target players each mill two cards. If you're the monarch, each of those players mills ten cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Ambassador Laquatus

Laquatus's Creativity

Target player draws cards equal to the number of cards in their hand, then discards that many cards.

Comparative Analysis

Surge {2}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Target player draws two cards.

Forget

Target player discards two cards, then draws as many cards as they discarded this way.

Coveted Peacock

Flying
Whenever Coveted Peacock attacks, you may goad target creature defending player controls. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Bamboozle

Target player reveals the top four cards of their library. You choose two of those cards and put them into that player's graveyard. Put the rest on top of their library in any 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.

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.

Lumengrid Augur

{1}, {T}: Target player draws a card, then discards a card. If that player discards an artifact card this way, untap Lumengrid Augur.

Cultural Exchange

Choose any number of creatures target player controls. Choose the same number of creatures another target player controls. Those players exchange control of those creatures. (This effect lasts indefinitely.)

Thought Scour

Target player mills two cards.
Draw a card.

Misstep

Creatures target player controls don't untap during that player's next untap step.

Inspiration

Inevitable Betrayal

Suspend 3—{1}{U}{U} (Rather than cast this card from your hand, pay {1}{U}{U} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search target opponent's library for a creature card and put that card onto the battlefield under your control. Then that player shuffles.

Capsize

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Return target permanent to its owner's hand.

Learn from the Past

Target player shuffles their graveyard into their library.
Draw a card.

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Fatigue

Target player skips their next draw step.

Huddle Up

Assist (Another player can pay up to {2} of this spell's cost.)
Two target players each draw a card.

Jace's Erasure

Whenever you draw a card, you may have target player mill a card.

Karn's Temporal Sundering

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Target player takes an extra turn after this one. Return up to one target nonland permanent to its owner's hand. Exile Karn's Temporal Sundering.

Pongify

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

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Arcane Signet

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

Careful Consideration

Target player draws four cards, then discards three cards. If you cast this spell during your main phase, instead that player draws four cards, then discards two cards.

Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

Disrupting Scepter

{3}, {T}: Target player discards a card. Activate only during your turn.

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards.

Gulf Squid

When Gulf Squid enters, tap all lands target player controls.

Split the Party

Choose target player. Return half the creatures they control to their owner's hand, rounded up.

Mana Vapors

Lands target player controls don't untap during their next untap step.

Commander's Insight

Target player draws X cards plus an additional card for each time they've cast a commander from the command zone this game.

Curse of Surveillance

Enchant player
At the beginning of enchanted player's upkeep, any number of target players other than that player each draw cards equal to the number of Curses attached to that player.

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.)

Cellar Door

{3}, {T}: Target player puts the bottom card of their library into their graveyard. If it's a creature card, you create a 2/2 black Zombie creature token.

Clear the Mind

Compelling Deterrence

Return target nonland permanent to its owner's hand. Then that player discards a card if you control a Zombie.

Drowner Initiate

Whenever a player casts a blue spell, you may pay {1}. If you do, target player mills two cards.

Mindslaver

{4}, {T}, Sacrifice Mindslaver: You control target player during that player's next turn. (You see all cards that player could see and make all decisions for the player.)

Drowned Secrets

Whenever you cast a blue spell, target player mills two cards.

Rapid Hybridization

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

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Curse of Inertia

Enchant player
Whenever a player attacks enchanted player with one or more creatures, that attacking player may tap or untap target permanent of their choice.

Dream Twist

Target player mills three cards.
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Merfolk Mesmerist

Eye Spy

Look at the top card of target player's library. You may put that card into their graveyard.