Harvestguard Alseids

Constellation — Whenever Harvestguard Alseids or another enchantment enters the battlefield under your control, prevent all damage that would be dealt to target creature this turn.

Ephara, God of the Polis

Indestructible
As long as your devotion to white and blue is less than seven, Ephara isn't a creature.
At the beginning of each upkeep, if you had another creature enter the battlefield under your control last turn, draw a card.

Hopeful Eidolon

Bestow {3}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Enchanted creature gets +1/+1 and has lifelink.

Perplexing Chimera

Whenever an opponent casts a spell, you may exchange control of Perplexing Chimera and that spell. If you do, you may choose new targets for the spell. (If the spell becomes a permanent, you control that permanent.)

Sigil of the Empty Throne

Whenever you cast an enchantment spell, create a 4/4 white Angel creature token with flying.

Alela, Artful Provocateur

Flying, deathtouch, lifelink
Other creatures you control with flying get +1/+0.
Whenever you cast an artifact or enchantment spell, create a 1/1 blue Faerie creature token with flying.

Hypnotic Siren

Bestow {5}{U}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying
You control enchanted creature.
Enchanted creature gets +1/+1 and has flying.

Flitterstep Eidolon

Bestow {5}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flitterstep Eidolon can't be blocked.
Enchanted creature gets +1/+1 and can't be blocked.

Grim Guardian

Constellation — Whenever Grim Guardian or another enchantment enters the battlefield under your control, each opponent loses 1 life.

Aegis of the Gods

You have hexproof. (You can't be the target of spells or abilities your opponents control.)

Archetype of Imagination

Creatures you control have flying.
Creatures your opponents control lose flying and can't have or gain flying.

Treasury Thrull

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever Treasury Thrull attacks, you may return target artifact, creature, or enchantment card from your graveyard to your hand.

Whitewater Naiads

Constellation — Whenever Whitewater Naiads or another enchantment enters the battlefield under your control, target creature can't be blocked this turn.

Fate Unraveler

Whenever an opponent draws a card, Fate Unraveler deals 1 damage to that player.

Ghostblade Eidolon

Bestow {5}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Double strike (This creature deals both first-strike and regular combat damage.)
Enchanted creature gets +1/+1 and has double strike.

Skybind

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

Doomwake Giant

Constellation — Whenever Doomwake Giant or another enchantment enters the battlefield under your control, creatures your opponents control get -1/-1 until end of turn.