The Lost Caverns of Ixalan

Brackish Blunder | Instant | | Return target creature to its owner's hand. If it was tapped, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.") | Daarken

Inverted Iceberg | Artifact | | When Inverted Iceberg enters the battlefield, mill a card, then draw a card. (To mill a card, put the top card of your library into your graveyard.) Craft with artifact {4}{U}{U} ({4}{U}{U}, Exile this artifact, Exile another artifact you control or an artifact card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.) | Campbell White

Oaken Siren | Artifact Creature | Siren Pirate | Flying, vigilance {T}: Add {U}. Spend this mana only to cast an artifact spell or activate an ability of an artifact source. | Lars Grant-West

Pirate Hat | Artifact | Equipment | Equipped creature gets +1/+1 and has "Whenever this creature attacks, draw a card, then discard a card." Equip Pirate {1} Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.) | Domenico Cava

River Herald Scout | Creature | Merfolk Scout | When River Herald Scout 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.) | Josu Hernaiz

Shipwreck Sentry | Creature | Human Pirate | Defender As long as an artifact entered the battlefield under your control this turn, Shipwreck Sentry can attack as though it didn't have defender. | Ryan Valle

Song of Stupefaction | Enchantment | Aura | Enchant creature or Vehicle When Song of Stupefaction enters the battlefield, you may mill two cards. (You may put the top two cards of your library into your graveyard.) Fathomless descent — Enchanted permanent gets -X/-0, where X is the number of permanent cards in your graveyard. | Ernanda Souza