Ixalan

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

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