Ixalan

Arcane Adaptation | Enchantment | | As Arcane Adaptation enters the battlefield, choose a creature type. Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield. | Mark Behm

Cancel | Instant | | Counter target spell. | Mathias Kollros

Deeproot Waters | Enchantment | | Whenever you cast a Merfolk spell, create a 1/1 blue Merfolk creature token with hexproof. (A creature with hexproof can't be the target of spells or abilities your opponents control.) | Zezhou Chen

Depths of Desire | Instant | | Return target creature to its owner's hand. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.") | John Stanko

Jace, Cunning Castaway | Legendary Planeswalker | Jace | +1: Whenever one or more creatures you control deal combat damage to a player this turn, draw a card, then discard a card. −2: Create a 2/2 blue Illusion creature token with "When this creature becomes the target of a spell, sacrifice it." −5: Create two tokens that are copies of Jace, Cunning Castaway, except they're not legendary. | Kieran Yanner

Kopala, Warden of Waves | Legendary Creature | Merfolk Wizard | Spells your opponents cast that target a Merfolk you control cost {2} more to cast. Abilities your opponents activate that target a Merfolk you control cost {2} more to activate. | Magali Villeneuve

Lookout's Dispersal | Instant | | This spell costs {1} less to cast if you control a Pirate. Counter target spell unless its controller pays {4}. | Ryan Yee

Navigator's Ruin | Enchantment | | Raid — At the beginning of your end step, if you attacked this turn, target opponent mills four cards. | Zoltan Boros

Sailor of Means | Creature | Human Pirate | When Sailor of Means enters the battlefield, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.") | Ryan Pancoast

Siren Lookout | Creature | Siren Pirate | Flying When Siren Lookout enters the battlefield, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.) | Chris Rallis

Storm Fleet Spy | Creature | Human Pirate | Raid — When Storm Fleet Spy enters the battlefield, if you attacked this turn, draw a card. | Scott Murphy

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

Shapers of Nature | Creature | Merfolk Shaman | {3}{G}: Put a +1/+1 counter on target creature. {2}{U}, Remove a +1/+1 counter from a creature you control: Draw a card. | Chris Seaman