msem-instigator

Prevent all damage target spell or permanent would deal this turn. You gain life equal to the damage prevented this way.

Deathtouch
Putrid Lurker can't block.
Whenever you discard Putrid Lurker or another card, you may pay {B}. If you do, return Putrid Lurker from your graveyard to the battlefield.

Whenever Yenzu Mindwrencher perseveres, each opponent discards a card. (A creature perseveres when it survives damage.)

Exile target creature. That creature's controller reveals cards from the top of their library until they reveal a creature card. That player puts that card onto the battlefield, then shuffles the rest into their library. If you own that card, it enters with an additional X +1/+1 counters on it, where X is its power.

Ward—Sacrifice three permanents.
At the beginning of your end step, put a desperation counter on End of History. Draw two cards for each counter on it, then exile the top three cards of your library for each counter on it.

Counter target spell. If a noncreature spell is countered this way, conjure a card named Fatigue and put it on top of your library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

Coastal Metropolis enters tapped unless you have 15 or less life.
{T}: Add {W} or {U}.

When Loyal Retriever dies, search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.
Foreshadow {5}{W} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Blind Soulcaller envisions an instant or sorcery card, you may tap target permanent.

Flying, deathtouch

{X}{W}{W}: Prevent the next X damage that would be dealt to target creature you control this turn. Whenever damage is prevented this way, you gain that much life.

Menace
Pay 2 life: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Sacrifice a permanent: Darna gets +1/+1 until end of turn.

Up to two target creatures you control each get +1/+0 and gain menace until end of turn.

Enchant creature
When Dark Desire enters, target player discards a card.
Whenever enchanted creature deals combat damage to a player, you draw a card and you lose 1 life.

Prevent all damage that would be dealt by creatures this turn.

Flying
When Depraved Imp enters, if you control a legendary creature, put two +1/+1 counters on Depraved Imp.

{T}, Sacrifice a land: Untap up to three target lands.

When Ninhasir's March enters, it deals 3 damage to any target.
{1}{R}{R}: Transform Ninhasir's March. Activate only if your fealty to Mountains is five or greater.

Flying
When Ghastly Spirit enters, mill four cards, then return a nonland card from your graveyard to your hand.

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Flash
When Atieh enters, return target noncreature spell to its owner's hand.
{W}{U}: Angel — You gain 2 life and draw a card.
{2}{W}{U}: Elder — Atieh gains “Each opponent can't cast more than one spell each turn.”

All creatures get -2/-2 until end of turn. Add {B}{B}.

Exile cards from the top of your library until you exile a nonland card. You may play one of those cards from exile until the end of your next turn.

Destroy target permanent. Trigger a death knell of any number of permanents you control.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever Paladin's Attendant encourages a creature, that creature gains first strike until end of turn.