Rivals of Ixalan

Cacophodon | Creature | Dinosaur | Enrage — Whenever Cacophodon is dealt damage, untap target permanent. | Johann Bodin

Forerunner of the Heralds | Creature | Merfolk Scout | When Forerunner of the Heralds enters the battlefield, you may search your library for a Merfolk card, reveal it, then shuffle and put that card on top. Whenever another Merfolk enters the battlefield under your control, put a +1/+1 counter on Forerunner of the Heralds. | Chris Seaman

Jadecraft Artisan | Creature | Merfolk Shaman | When Jadecraft Artisan enters the battlefield, target creature gets +2/+2 until end of turn. | Izzy

Knight of the Stampede | Creature | Human Knight | Dinosaur spells you cast cost {2} less to cast. | Steve Argyle

World Shaper | Creature | Merfolk Shaman | Whenever World Shaper attacks, you may mill three cards. When World Shaper dies, return all land cards from your graveyard to the battlefield tapped. | Raymond Swanland

Raging Regisaur | Creature | Dinosaur | Whenever Raging Regisaur attacks, it deals 1 damage to any target. | Bayard Wu