Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Master of the Pearl Trident

Other Merfolk creatures you control get +1/+1 and have islandwalk. (They can't be blocked as long as defending player controls an Island.)

Silvergill Adept

As an additional cost to cast this spell, reveal a Merfolk card from your hand or pay {3}.
When Silvergill Adept enters the battlefield, draw a card.

Planar Incision

Exile target artifact or creature, then return it to the battlefield under its owner's control with a +1/+1 counter on it.

Yorion, Sky Nomad

Companion — Your starting deck contains at least twenty cards more than the minimum deck size. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Flying
When Yorion enters the battlefield, exile any number of other nonland permanents you own and control. Return those cards to the battlefield at the beginning of the next end step.

Meneldor, Swift Savior

Flying
Whenever Meneldor, Swift Savior deals combat damage to a player, exile up to one target creature you own, then return it to the battlefield under your control.

Merrow Reejerey

Other Merfolk creatures you control get +1/+1.
Whenever you cast a Merfolk spell, you may tap or untap target permanent.

Sea Gate Oracle

When Sea Gate Oracle enters the battlefield, look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.

The Surgical Bay

The Surgical Bay enters the battlefield tapped.
{T}: Add {U}.
{1}{U}, {T}, Sacrifice The Surgical Bay: Draw a card.

Man-o'-War

When Man-o'-War enters the battlefield, return target creature to its owner's hand.

Scroll Thief

Whenever Scroll Thief deals combat damage to a player, draw a card.

Hidden Cataract

Hidden Cataract enters the battlefield tapped.
{T}: Add {U}.
{4}{U}, {T}, Sacrifice Hidden Cataract: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 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.)

Archaeomancer

When Archaeomancer enters the battlefield, return target instant or sorcery card from your graveyard to your hand.

Vapor Snag

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

Island

Sleep

Tap all creatures target player controls. Those creatures don't untap during that player's next untap step.

Merfolk Looter

Counterspell

Displace

Exile up to two target creatures you control, then return those cards to the battlefield under their owner's control.

Mulldrifter

Flying
When Mulldrifter enters the battlefield, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Triton Shorestalker

Wing Splicer

When Wing Splicer enters the battlefield, create a 3/3 colorless Phyrexian Golem artifact creature token.
Golem creatures you control have flying.

Winter Eladrin

Gust of Wind — When Winter Eladrin enters the battlefield, return up to one other target creature to its owner's hand.

Mist-Cloaked Herald

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.)

Mystic Sanctuary

({T}: Add {U}.)
Mystic Sanctuary enters the battlefield tapped unless you control three or more other Islands.
When Mystic Sanctuary enters the battlefield untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Circuit Mender

When Circuit Mender enters the battlefield, you gain 2 life.
When Circuit Mender leaves the battlefield, draw a card.

Lonely Sandbar

Lonely Sandbar enters the battlefield tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Watertrap Weaver

When Watertrap Weaver enters the battlefield, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.