Theros Beyond Death

Hydra's Growth | Enchantment | Aura | Enchant creature When Hydra's Growth enters the battlefield, put a +1/+1 counter on enchanted creature. At the beginning of your upkeep, double the number of +1/+1 counters on enchanted creature. | Bayard Wu

Nyx Herald | Enchantment Creature | Centaur Shaman | At the beginning of combat on your turn, target enchanted creature or enchantment creature you control gets +1/+1 and gains trample until end of turn. | Mark Zug

Setessan Petitioner | Creature | Human Druid | When Setessan Petitioner enters the battlefield, you gain life equal to your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.) | Livia Prima

Siona, Captain of the Pyleas | Legendary Creature | Human Soldier | When Siona, Captain of the Pyleas enters the battlefield, look at the top seven cards of your library. You may reveal an Aura card from among them and put it into your hand. Put the rest on the bottom of your library in a random order. Whenever an Aura you control becomes attached to a creature you control, create a 1/1 white Human Soldier creature token. | Chris Rallis

Eutropia the Twice-Favored | Legendary Creature | Human Wizard | Constellation — Whenever an enchantment enters the battlefield under your control, put a +1/+1 counter on target creature. That creature gains flying until end of turn. | Sara Winters

Warden of the Chained | Creature | Minotaur Warrior | Trample Warden of the Chained can't attack unless you control another creature with power 4 or greater. | Steve Prescott