Protection from red

Elemental creatures you control get +1/+1.

When Master of Waves enters the battlefield, create a number of 1/0 blue Elemental creature tokens equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

{T}: Draw a card, then discard a card.

Other Merfolk creatures you control get +1/+1.

{T}: Target Merfolk creature can’t be blocked this turn.

Flying

When Merfolk Wayfinder enters the battlefield, reveal the top three cards of your library. Put all Island cards revealed this way into your hand and the rest on the bottom of your library in any order.

Other Merfolk creatures you control get +1/+1.

Whenever you cast a Merfolk spell, you may tap or untap target permanent.

Draw X cards.

You may exile a blue card from your hand rather than pay this spell’s mana cost.

Change the target of target spell with a single target.

({T}: Add {R}.)

({T}: Add {R}.)

({T}: Add {R}.)

({T}: Add {R}.)

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

{T}: Rootwater Hunter deals 1 damage to any target.

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

{T}: Target Merfolk creature gets +1/+1 and gains islandwalk until end of turn. (It can’t be blocked as long as defending player controls an Island.)

{T}: Target land becomes an Island until end of turn.

Tarfire deals 2 damage to any target.

When Tidal Courier enters the battlefield, reveal the top four cards of your library. Put all Merfolk cards revealed this way into your hand and the rest on the bottom of your library in any order.

{3}{U}: Tidal Courier gains flying until end of turn.

{T}: Target land becomes an Island until end of turn.

Create a 5/5 blue Wall creature token with defender. Sacrifice it at the beginning of the next end step.

When Tidebinder Mage enters the battlefield, tap target red or green creature an opponent controls. That creature doesn’t untap during its controller’s untap step for as long as you control Tidebinder Mage.