Surrakar Spellblade

Whenever you cast an instant or sorcery spell, you may put a charge counter on Surrakar Spellblade.
Whenever Surrakar Spellblade deals combat damage to a player, you may draw X cards, where X is the number of charge counters on it.

Surrakar Banisher

When Surrakar Banisher enters, you may return target tapped creature to its owner's hand.

Merfolk Seastalkers

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
{2}{U}: Tap target creature without flying.

Amphin Cutthroat

Merrow Levitator

{T}: Target creature gains flying until end of turn.
Whenever you cast a blue spell, you may untap Merrow Levitator.

Bog Wraith

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Kraken Hatchling

Cloaked Siren

Flash (You may cast this spell any time you could cast an instant.)
Flying

Cursecatcher

Sacrifice Cursecatcher: Counter target instant or sorcery spell unless its controller pays {1}.

Alluring Siren

{T}: Target creature an opponent controls attacks you this turn if able.

Tidal Force

At the beginning of each upkeep, you may tap or untap target permanent.

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.

Rotted Hulk

Merrow Bonegnawer

{T}: Target player exiles a card from their graveyard.
Whenever you cast a black spell, you may untap Merrow Bonegnawer.

Surrakar Marauder

Landfall — Whenever a land you control enters, Surrakar Marauder gains intimidate until end of turn. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Merrow Wavebreakers

{1}{U}, {Q}: Merrow Wavebreakers gains flying until end of turn. ({Q} is the untap symbol.)

Dakra Mystic

{U}, {T}: Each player reveals the top card of their library. You may put the revealed cards into their owners' graveyards. If you don't, each player draws a card.