Perplexing Chimera

Whenever an opponent casts a spell, you may exchange control of Perplexing Chimera and that spell. If you do, you may choose new targets for the spell. (If the spell becomes a permanent, you control that permanent.)

Waterknot

Enchant creature
When Waterknot enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Merfolk Skyscout

Flying
Whenever Merfolk Skyscout attacks or blocks, untap target permanent.

Vesuvan Shapeshifter

As Vesuvan Shapeshifter enters or is turned face up, you may choose another creature on the battlefield. If you do, until Vesuvan Shapeshifter is turned face down, it becomes a copy of that creature, except it has "At the beginning of your upkeep, you may turn this creature face down."
Morph {1}{U}

Darksteel Citadel

Unstable Shapeshifter

Whenever another creature enters, Unstable Shapeshifter becomes a copy of that creature, except it has this ability.

Merfolk Sovereign

Other Merfolk creatures you control get +1/+1.
{T}: Target Merfolk creature can't be blocked this turn.

Jace, the Mind Sculptor

+2: Look at the top card of target player's library. You may put that card on the bottom of that player's library.
0: Draw three cards, then put two cards from your hand on top of your library in any order.
−1: Return target creature to its owner's hand.
−12: Exile all cards from target player's library, then that player shuffles their hand into their library.

Negate

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.")

Riptide Shapeshifter

{2}{U}{U}, Sacrifice Riptide Shapeshifter: Choose a creature type. Reveal cards from the top of your library until you reveal a creature card of that type. Put that card onto the battlefield and shuffle the rest into your library.

Faerie Artisans

Flying
Whenever a nontoken creature an opponent controls enters, create a token that's a copy of that creature except it's an artifact in addition to its other types. Then exile all other tokens created with Faerie Artisans.

Faerie Formation

Flying
{3}{U}: Create a 1/1 blue Faerie creature token with flying. Draw a card.

Moonring Island

({T}: Add {U}.)
Moonring Island enters tapped.
{U}, {T}: Look at the top card of target player's library. Activate only if you control two or more blue permanents.

Faerie Vandal

Flash (You may cast this spell any time you could cast an instant.)
Flying
Whenever you draw your second card each turn, put a +1/+1 counter on Faerie Vandal.

Shapeshifter's Marrow

At the beginning of each opponent's upkeep, that player reveals the top card of their library. If it's a creature card, the player puts the card into their graveyard and Shapeshifter's Marrow becomes a copy of that card. (If it does, it loses this ability.)

Faerie Conclave

Faerie Conclave enters tapped.
{T}: Add {U}.
{1}{U}: Faerie Conclave becomes a 2/1 blue Faerie creature with flying until end of turn. It's still a land.

Stitcher Geralf

{2}{U}, {T}: Each player mills three cards. Exile up to two creature cards put into graveyards this way. Create an X/X blue Zombie creature token, where X is the total power of the cards exiled this way.

Merfolk Trickster

Flash
When Merfolk Trickster enters, tap target creature an opponent controls. It loses all abilities until end of turn.

Countervailing Winds

Counter target spell unless its controller pays {1} for each card in your graveyard.
Cycling {2} ({2}, Discard this card: Draw a card.)

Merfolk Spy

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Merfolk Spy deals combat damage to a player, that player reveals a card at random from their hand.

Faerie Harbinger

Flash
Flying
When Faerie Harbinger enters, you may search your library for a Faerie card, reveal it, then shuffle and put that card on top.

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

Waterspout Weavers

Kinship — At the beginning of your upkeep, you may look at the top card of your library. If it shares a creature type with Waterspout Weavers, you may reveal it. If you do, each creature you control gains flying until end of turn.

Merfolk Thaumaturgist

{T}: Switch target creature's power and toughness until end of turn.

Counterspell

Time Spiral

Exile Time Spiral. Each player shuffles their hand and graveyard into their library, then draws seven cards. You untap up to six lands.

Memory Erosion

Whenever an opponent casts a spell, that player mills two cards.

Faerie Duelist

Flash
Flying
When Faerie Duelist enters, target creature an opponent controls gets -2/-0 until end of turn.

Counterintelligence

Return one or two target creatures to their owners' hands.

Cackling Counterpart

Create a token that's a copy of target creature you control.
Flashback {5}{U}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Faerie Trickery

Counter target non-Faerie spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Omniscience

You may cast spells from your hand without paying their mana costs.

Time Reversal

Each player shuffles their hand and graveyard into their library, then draws seven cards. Exile Time Reversal.

Propaganda

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

Didn't Say Please

Counter target spell. Its controller mills three cards.

Counterbore

Counter target spell. Search its controller's graveyard, hand, and library for all cards with the same name as that spell and exile them. Then that player shuffles.

Renegade Map

Renegade Map enters tapped.
{T}, Sacrifice Renegade Map: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Escaped Shapeshifter

As long as an opponent controls a creature with flying not named Escaped Shapeshifter, Escaped Shapeshifter has flying. The same is true for first strike, trample, and protection from any color.

Oath of Scholars

At the beginning of each player's upkeep, that player chooses target player who has more cards in hand than they do and is their opponent. The first player may discard their hand and draw three cards.

Waterwhirl

Return up to two target creatures to their owners' hands.

Counterlash

Counter target spell. You may cast a spell that shares a card type with it from your hand without paying its mana cost.

Telepathy

Your opponents play with their hands revealed.

Counterbalance

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, counter that spell if it has the same mana value as the revealed card.

Countermand

Counter target spell. Its controller mills four cards.

Waterspout Elemental

Kicker {U} (You may pay an additional {U} as you cast this spell.)
Flying
When Waterspout Elemental enters, if it was kicked, return all other creatures to their owners' hands and you skip your next turn.

Magosi, the Waterveil

Magosi, the Waterveil enters tapped.
{T}: Add {U}.
{U}, {T}: Put an eon counter on Magosi, the Waterveil. Skip your next turn.
{T}, Remove an eon counter from Magosi, the Waterveil and return it to its owner's hand: Take an extra turn after this one.

Flash Counter

Jace, Memory Adept

+1: Draw a card. Target player mills a card.
0: Target player mills ten cards.
−7: Any number of target players each draw twenty cards.

Volrath's Shapeshifter

As long as the top card of your graveyard is a creature card, Volrath's Shapeshifter has the full text of that card and has the text "{2}: Discard a card." (Volrath's Shapeshifter has that card's name, mana cost, color, types, abilities, power, and toughness.)
{2}: Discard a card.

Talrand, Sky Summoner

Whenever you cast an instant or sorcery spell, create a 2/2 blue Drake creature token with flying.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Titan Forge

{3}, {T}: Put a charge counter on Titan Forge.
{T}, Remove three charge counters from Titan Forge: Create a 9/9 colorless Golem artifact creature token.

Island

Contagion Clasp

When Contagion Clasp enters, put a -1/-1 counter on target creature.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Jace, Telepath Unbound

+1: Up to one target creature gets -2/-0 until your next turn.
−3: You may cast target instant or sorcery card from your graveyard this turn. If that spell would be put into your graveyard, exile it instead.
−9: You get an emblem with "Whenever you cast a spell, target opponent mills five cards."

Jace, Vryn's Prodigy

{T}: Draw a card, then discard a card. If there are five or more cards in your graveyard, exile Jace, Vryn's Prodigy, then return him to the battlefield transformed under his owner's control.

Jace, Vryn's Prodigy // Jace, Telepath Unbound

Jwari Shapeshifter

You may have Jwari Shapeshifter enter as a copy of any Ally creature on the battlefield.