msem-instigator

Whenever you cast a spell, you may pay {1}. If you do, Wizened Tortle explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then you may put that card in your graveyard.)

Vigilance
Whenever a creature you control survives damage, it explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then you may put that card in your graveyard.)

[+2]: Put a -1/-1 counter on or remove a -1/-1 counter from up to one target creature.
[–1]: Draw a card, then each player sacrifices a nonland permanent.
[–10]: Destroy all nonland permanents you don't control.

Haste
When Wretched Merfolk enters, target creature can't block this turn.

Counter target spell. If that spell is countered this way, put it on the bottom of its owner's library instead of putting it into its owner's graveyard. You may put up to three target cards from your graveyard on the bottom of your library in any order.

Exile target creature or planeswalker and up to one target card from its controller's graveyard.

Search your library for a creature card with mana value 3 or less, put it onto the battlefield, then shuffle. It gains haste until end of turn. Return it to your hand at the beginning of the end step.

Whenever Adept Lieutenant attacks, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
{1}, Sacrifice an Idol: Put a +1/+1 counter on Adept Lieutenant.

Create two 1/1 white Bird creature tokens with flying.

When Aerie Bell-Warden enters, if it's in a pack, you gain 5 life. (Two or more creatures you control with equal power are in a pack.)

When Aftermath of the Surge enters, create two Treasure tokens.
{1}{U}, Sacrifice two artifacts: Draw two cards.
{3}{U}, Sacrifice four artifacts: Create an 8/8 blue Kraken creature token. It can't block this turn.

Flash
When Agent of Equilibrium enters, destroy target creature or planeswalker an opponent controls that was dealt damage this turn.

Draw a card.
Showcase {3}{U} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

(Choose only one work as a sorcery to add its ability.)
When Altar of Twisted Piety enters, return target creature card with mana value 3 or less from your graveyard to the battlefield.
{2}{B}: Shadows Bind Us
{B}, Sacrifice three creatures: Create a 5/5 black Demon creature token. Put your choice of a flying counter or a lifelink counter on it. It can't block this turn.
{2}{R}: Hellfire Fills Us
{R}, Sacrifice a creature: Altar of Twisted Piety deals 2 damage to any target.

Ward {2}
When Ancient of Lotus Lake enters, draw a card.

Flying
When Ancient of Reflections enters, create a token that's a copy of target creature you control not named Ancient of Reflections, except it's 1/1 and has haste. Sacrifice it at end of turn.

Flying
When Apogee Cranes enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Apostle of the Elders has lifelink as long as it has a +1/+1 counter on it.

Whenever Apostle of the Spirit Moon becomes blocked by a creature, Apostle of the Spirit Moon deals 1 damage to that creature and that creature's controller.

Apothecary's Gift deals 5 damage to target creature or planeswalker. You gain life equal to the excess damage dealt this way.

Target creature you control gets +2/+2 until end of turn. If it's attacking, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

When Arrogant Orator enters, create a 0/1 black Cultist creature token with “{1}{B}{B}, Sacrifice three Cultists: Create a 5/5 black Demon creature token.”

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Exile up to two target creatures. Return them to the battlefield under their owners' control at the beginning of the next end step.
3 | You may have them enter with an additional +1/+1 counter on them.

Flying
When Ascetic of the Folded Fan enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Each creature you control with a +1/+1 counter on it has vigilance.

Flying
When Aspect of Divinity dies, create a 0/2 red Egg creature token with “When this creature dies, return target creature card with mana value 2 or less from your graveyard to the battlefield.”