Treacherous Blessing

When Treacherous Blessing enters, draw three cards.
Whenever you cast a spell, you lose 1 life.
When Treacherous Blessing becomes the target of a spell or ability, sacrifice it.

Hatching Plans

When Hatching Plans is put into a graveyard from the battlefield, draw three cards.

Enigmatic Incarnation

At the beginning of your end step, you may sacrifice another enchantment. If you do, search your library for a creature card with mana value equal to 1 plus the sacrificed enchantment's mana value, put that card onto the battlefield, then shuffle.

Grim Guardian

Constellation — Whenever Grim Guardian or another enchantment you control enters, each opponent loses 1 life.

Doomwake Giant

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

Nightmare Shepherd

Flying
Whenever another nontoken creature you control dies, you may exile it. If you do, create a token that's a copy of that creature, except it's 1/1 and it's a Nightmare in addition to its other types.

Aphemia, the Cacophony

Flying
At the beginning of your end step, you may exile an enchantment card from your graveyard. If you do, create a 2/2 black Zombie creature token.

Archfiend of Depravity

Flying
At the beginning of each opponent's end step, that player chooses up to two creatures they control, then sacrifices the rest.

Omen of the Sea

Flash (You may cast this spell any time you could cast an instant.)
When Omen of the Sea enters, scry 2, then draw a card.
{2}{U}, Sacrifice Omen of the Sea: Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)