The Lost Caverns of Ixalan

Cogwork Wrestler | Artifact Creature | Gnome | Flash When Cogwork Wrestler enters the battlefield, target creature an opponent controls gets -2/-0 until end of turn. | Tomek Larek

Didact Echo | Creature | Spirit Cleric | When Didact Echo enters the battlefield, draw a card. Descend 4 — Didact Echo has flying as long as there are four or more permanent cards in your graveyard. | Irina Nordsol

Frilled Cave-Wurm | Creature | Salamander Wurm | Descend 4 — Frilled Cave-Wurm gets +2/+0 as long as there are four or more permanent cards in your graveyard. | Aaron Miller

Marauding Brinefang | Creature | Dinosaur | Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.) Islandcycling {2} ({2}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.) | John Tedrick

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

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

Sage of Days | Creature | Human Wizard | When Sage of Days enters the battlefield, look at the top three cards of your library. You may put one of those cards back on top of your library. Put the rest into your graveyard. | Aldo Domínguez

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

Waterwind Scout | Creature | Merfolk Scout | Flying When Waterwind Scout enters the battlefield, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.") | Alix Branwyn

Waylaying Pirates | Creature | Human Pirate | When Waylaying Pirates enters the battlefield, if you control an artifact, tap target artifact or creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.) | Zoltan Boros