Merfolk Looter

Skyshaper

Sacrifice Skyshaper: Creatures you control gain flying until end of turn.

Mana Breach

Whenever a player casts a spell, that player returns a land they control to its owner's hand.

Robe of Mirrors

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature has shroud. (It can't be the target of spells or abilities.)

Theft of Dreams

Draw a card for each tapped creature target opponent controls.

Erratic Portal

{1}, {T}: Return target creature to its owner's hand unless its controller pays {1}.

Ertai, Wizard Adept

Rootwater Mystic

{1}{U}: Look at the top card of target player's library.

Equilibrium

Whenever you cast a creature spell, you may pay {1}. If you do, return target creature to its owner's hand.

Mind Over Matter

Discard a card: You may tap or untap target artifact, creature, or land.

Treasure Trove

Whiptongue Frog

{U}: Whiptongue Frog gains flying until end of turn.

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.

Dominating Licid

{1}{U}{U}, {T}: Dominating Licid loses this ability and becomes an Aura enchantment with enchant creature. Attach it to target creature. You may pay {U} to end this effect.
You control enchanted creature.

Wall of Kelp

Defender (This creature can't attack.)
{U}{U}, {T}: Create a 0/1 blue Plant Wall creature token with defender named Kelp.

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.

Scrivener

When Scrivener enters, you may return target instant card from your graveyard to your hand.

Keeper of the Mind

{U}, {T}: Choose target opponent who has at least two more cards in hand than you do as you activate this ability. Draw a card.

Fade Away

For each creature, its controller sacrifices a permanent of their choice unless they pay {1}.

Merchant Scroll

Search your library for a blue instant card, reveal that card, put it into your hand, then shuffle.

Thalakos Scout

Shadow (This creature can block or be blocked by only creatures with shadow.)
Discard a card: Return Thalakos Scout to its owner's hand.