Gylwain, Casting Director

Whenever Gylwain, Casting Director or another nontoken creature you control enters, choose one —
• Create a Royal Role token attached to that creature.
• Create a Sorcerer Role token attached to that creature.
• Create a Monster Role token attached to that creature.

Rite of Harmony

Whenever a creature or enchantment you control enters this turn, draw a card.
Flashback {2}{G}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Ajani's Chosen

Whenever an enchantment you control enters, create a 2/2 white Cat creature token. If that enchantment is an Aura, you may attach it to the token.

Skybind

Constellation — Whenever Skybind or another enchantment you control enters, exile target nonenchantment permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Strength from the Fallen

Constellation — Whenever Strength from the Fallen or another enchantment you control enters, target creature gets +X/+X until end of turn, where X is the number of creature cards in your graveyard.