Rivals of Ixalan

Legion Lieutenant | Creature | Vampire Knight | Other Vampires you control get +1/+1. | Zezhou Chen

Path of Mettle | Legendary Enchantment | | When Path of Mettle enters the battlefield, it deals 1 damage to each creature that doesn't have first strike, double strike, vigilance, or haste. Whenever you attack with at least two creatures that have first strike, double strike, vigilance, and/or haste, transform Path of Mettle. | Victor Adame Minguez

Relentless Raptor | Creature | Dinosaur | Vigilance Relentless Raptor attacks or blocks each combat if able. | Matt Stewart

Siegehorn Ceratops | Creature | Dinosaur | Enrage — Whenever Siegehorn Ceratops is dealt damage, put two +1/+1 counters on it. (It must survive the damage to get the counters.) | Filip Burburan

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