Ixalan

Deeproot Warrior | Creature | Merfolk Warrior | Whenever Deeproot Warrior becomes blocked, it gets +1/+1 until end of turn. | Slawomir Maniak

Ixalli's Diviner | Creature | Human Druid | When Ixalli's Diviner 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.) | Lucas Graciano

Ixalli's Keeper | Creature | Human Shaman | {7}{G}, {T}, Sacrifice Ixalli's Keeper: Target creature gets +5/+5 and gains trample until end of turn. | Lake Hurwitz

Pounce | Instant | | Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.) | Lucas Graciano

River Heralds' Boon | Instant | | Put a +1/+1 counter on target creature and a +1/+1 counter on up to one target Merfolk. | Alex Konstad