msem-instigator

[+1]: Until your next turn, whenever up to one target permanent deals damage to another permanent or player, it deals that much damage to itself.
[–X]: When you next cast a noncreature spell with mana value X or less this turn, copy it. You may choose new targets for the copy.
[–2]: Create an X/X blue Spirit creature token, where X is the number of colors of mana you've spent to cast spells this turn.

Choose one —
• Each player skips their next combat step.
• Each opponent can't cast instant or sorcery spells this turn.

Enchant player
If enchanted player would shuffle their library, instead that player chooses a permanent they control and a card from their hand, shuffles them into their owner's libraries, then loses 3 life.

Menace
Whenever one or more creature cards leave your graveyard, put a +1/+1 counter on Mausoleum Resident. It gains lifelink until end of turn.

Target opponent sacrifices half the permanents they control, rounded down.

Unstoppable Slaughter deals 1 damage to each creature and each player. Whenever a creature dealt damage by Unstoppable Slaughter this turn dies this turn, repeat that process.

Flash
When Remnant Spotter enters, put target permanent card from your graveyard on top of your library.

Nonbasic lands have “Whenever this land becomes tapped, you lose 1 life unless you sacrifice this land.”

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Tap target creature and put two stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Choose one —
• Counter target spell unless its controller pays {2}.
• Draw a card.

Whenever one or more creatures die for the first time each turn, you draw a card and you lose 1 life.
Whenever you cast a black noncreature spell, Villainy deals 2 damage to any target and you gain 2 life.

Scorch deals 3 damage to any target.

Target creature gets +2/+2 until end of turn.
Wanderlust — If you control four or more differently named lands, that creature gets +4/+4 until end of turn instead.

Whenever you cast a noncreature spell, upgrade Embodied Soul. (Give it one of the listed counters it doesn't already have.)
• Flying
• First strike
• Vigilance
• Lifelink
{W}: Until end of turn, if Embodied Soul isn't a creature, it becomes a 0/0 Spirit Avatar enchantment creature with “This creature gets +1/+1 for each different kind of counter on it.”

Lifelink
When Stalked Healer enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

When Ancestral Council enters, search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

Flash
When Veilborn Meddler enters, counter target spell if its mana value is less than or equal to Veilborn Meddler's power.
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Veilborn Meddler.

Whenever Crain's Crony enters or attacks, reveal the top card of your library and put it into your hand. You lose life equal to that card's mana value.
At the beginning of each end step, if you didn't lose life this turn, you lose the game.

Whenever Yri, the Daring Blade and exactly one other creature attack, Yri and that creature can't be blocked by creatures with mana value 3 or less this turn.

This spell can't be countered.
When Auros enters, it deals damage to any target equal to your devotion to red. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)
{R}, Sacrifice Auros, Discard your hand: Draw three cards.

[+2]: Create a 2/2 red Werewolf creature token with first strike and haste.
[–3]: Tanya deals 3 damage to each creature that's not a Wolf or a Werewolf.
[–8]: For each permanent your opponents control, that player sacrifices it unless they have Tanya deal 2 damage to them.

[+1]: Tanya, the Mooncursed becomes a legendary 3/1 red Werewolf creature with first strike until end of turn.
[–2]: Tanya, the Mooncursed deals 3 damage to target creature or planeswalker.
[–4]: Destroy target nonbasic colorless permanent.

You may play an additional land this turn.
Draw a card.

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Whenever Wild Lifescale attacks, proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Advance {1}{R}{W}{B} (Cast this for {1}{R}{W}{B} to advance it as it enters. {1}{R}{W}{B}: Advance this as a sorcery.)
Whenever Blastburn Angel advances, it gets +1/+1 and gains flying until end of turn. It deals 1 damage to each other creature.