Rivals of Ixalan

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

Cherished Hatchling | Creature | Dinosaur | When Cherished Hatchling dies, you may cast Dinosaur spells this turn as though they had flash, and whenever you cast a Dinosaur spell this turn, it gains "When this creature enters the battlefield, you may have it fight another target creature." | Sam Rowan

Crested Herdcaller | Creature | Dinosaur | Trample When Crested Herdcaller enters the battlefield, create a 3/3 green Dinosaur creature token with trample. | Lucas Graciano

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

Swift Warden | Creature | Merfolk Warrior | Flash When Swift Warden enters the battlefield, target Merfolk you control gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.) | Viktor Titov

Thrashing Brontodon | Creature | Dinosaur | {1}, Sacrifice Thrashing Brontodon: Destroy target artifact or enchantment. | Jakub Kasper

Atzocan Seer | Creature | Human Druid | {T}: Add one mana of any color. Sacrifice Atzocan Seer: Return target Dinosaur card from your graveyard to your hand. | Joseph Meehan

Merfolk Mistbinder | Creature | Merfolk Shaman | Other Merfolk you control get +1/+1. | Clint Cearley

Jungle Creeper | Creature | Elemental | {3}{B}{G}: Return Jungle Creeper from your graveyard to your hand. | Matt Stewart

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