msem-instigator

Dekinn, Depths Spirit can't attack or block unless a player has lost 3 or more life this turn.
At the beginning of each player's upkeep, that player may create a Mountain token. If they do, Dekinn deals 3 damage to them.
When Dekinn dies or is put into exile from the battlefield, you may put him into his owner's library third from the top.

Legendary creatures you control get +1/+1.

When Esiara, Skycaster's Infiltrator enters, exile target spell with mana value 4 or less.
{1}{U}{U}, Discard two cards: Exile Esiara, then return it to the battlefield under your control.
{2}{U}{U}, {T}, Exile Esiara: Until end of turn, you may play cards you don't own from exile.

You may cast Hunter of the Moon-Serpent from your graveyard as long as you gained life this turn.

Return target creature card with mana value 3 or less from your graveyard to the battlefield. Put a +1/+1 counter on it. It gains indestructible until end of turn.

Whenever a land you control enters, target creature gains your choice of flying or lifelink until end of turn.

Target creature gets -6/-6 until end of turn.
Create a black enchantment token named Blight with “At the beginning of your upkeep, you lose 1 life.”

[+2]: Create a 3/3 red Wurm creature token.
[–2]: Up to three target creatures each get +2/+2 until end of turn. Bessie deals 2 damage to each of up to three target creatures.
[–9]: You get an emblem with “Creatures you control have base power and toughness 7/7 and have indestructible.”

First strike
Whenever The Heart-hardened or another creature you control dies, each opponent loses 1 life. If this is the third time this ability has resolved this turn, you draw three cards and you lose 3 life.

As an instant or sorcery spell not cast from exile resolves, exile it instead of putting it anywhere else.
Once each turn, you may cast a card exiled with Eidetic Memory.

Haste
Rapport — Whenever Maghbri Hunter and at least one other creature you control become tapped, Maghbri Hunter gets +2/+1 until end of turn.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Return up to two target creatures an opponent controls to their owner's hand.
3 | That player puts one card from their hand on top of their library, and another on the bottom.

{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.

Whenever another creature you control dies, put a +1/+1 counter on Carnage Gorger.

Flying, menace
When Dreadfire Tyrant enters, target opponent reveals their hand. You may put a creature or planeswalker card from it onto the battlefield under your control. That permanent gains haste and “At the beginning of your end step, sacrifice a permanent you control.”
When Dreadfire Tyrant dies, each opponent loses 5 life. You gain life equal to the life lost this way.

Flash
Prowess
When High Rollers Esteemed enters, you may choose new targets for target spell or ability unless its controller has High Rollers Esteemed deal 4 damage to them.

Spells your opponents cast cost {1} more to cast.
Spells you cast cost {1} less to cast.

When Night Howlers enters, target opponent reveals three cards from their hand and you choose one of them. Exile that card until Night Howlers leaves the battlefield.

Artifacts you control have “{T}: Add one mana of any color.”
{2}{R}{G}: Create a 3/2 green Crocodile creature token with trample. It gains haste until end of turn.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast your first instant or sorcery spell each turn, copy that spell. You may choose new targets for the copies.

At the beginning of your upkeep, sacrifice a non-Snake creature or Boon of the Pacts. Then create a 1/1 black Snake creature token with deathtouch.
At the beginning of your draw step, draw an additional card.
Spells you cast cost {1} less to cast.

{2}{B}, Sacrifice Determined Slayer: Exile up to three target cards from target player's graveyard. They lose that much life.

Enchant land
Enchanted land has “{T}: Exile the top card of your library. If it's a nonland card, you may cast that card this turn.”

{T}, Sacrifice Merchant's District: Search your library for an Island or Mountain card and put it onto the battlefield tapped, then shuffle.