msem-instigator

Choose one. If an opponent lost 3 or more life this turn, choose any number instead.
• Target player sacrifices a legendary creature.
• Target player reveals their hand. You choose a nonland card from it. That player discards that card.
• Exile target player's graveyard.

At the beginning of each player's upkeep, that player loses 2 life unless they sacrifice a creature.
{4}{G}: Create a 2/2 green Wolf Elemental creature token.

Equipped creature gets +2/+2.
Whenever equipped creature attacks, you may return target creature card with mana value 2 or less from your graveyard to the battlefield.
Equip {2}

Choose two —
• Each opponent sacrifices a creature.
• Each player discards two cards.
• All creatures get -1/-1 until end of turn.
• You draw two cards and you lose 2 life.

Until end of turn, you may play cards from your graveyard by paying 2 life in addition to those cards' costs.
If a card would be put into your graveyard from anywhere this turn, exile that card instead.

Enchant opponent
Whenever enchanted player is attacked, up to one target attacking creature gains menace and lifelink until end of turn.

When Kill This Love enters, target opponent sacrifices a creature.
At the beginning of each end step, if a creature died this turn, you gain 2 life.

Destroy target creature. If you do, you may put a +1/+1 counter on a creature you control.

Equipped creature gets +2/+2.
Art of war — At the beginning of your end step, if equipped creature dealt damage to an opponent this turn, you may return target creature card from your graveyard to your hand.
Equip {2}

Destroy target creature.

Legacy (You may play this side of this card only from your graveyard. Exile it if it would be put into a graveyard or not resolve.)
Target creature gets -4/-4 until end of turn. When that creature dies this turn, other creatures its controller controls get -1/-1 until end of turn.

At the beginning of your upkeep, target player draws a card and loses 1 life. Each other player creates a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Once each turn, when a player loses life, you may harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Each opponent loses 1 life and you gain that much life.

Exile target creature or planeswalker. You gain 4 life.

Destroy target creature or planeswalker. Create a 1/1 black Rat creature token with “This creature can't block.”

Enchant player
At the beginning of enchanted player's upkeep, that player loses 1 life and you gain 1 life.

As an additional cost to cast this spell, sacrifice a creature.
Target creature gains +4/+4 until end of turn.

Each player chooses a nonland permanent they control, then sacrifices the rest.

Enchant creature
As Legacy of Frondpond enters, choose a creature type.
Enchanted creature gets +2/+1, has deathtouch, and is the chosen type in addition to its other types.

Put target creature on the bottom of its owner's library.
Each player conjures a card named Fatigue and puts it on top of their library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

You draw two cards and you lose 2 life. Each opponent draws a card.

When Lethal Storyboarding enters, create two 1/1 colorless Construct Actor creature tokens.
Whenever a creature you control deals combat damage to a player or planeswalker, sacrifice it. When you do, choose one —
• Return a creature card with mana value 3 or less from your graveyard to the battlefield tapped.
• Draw a card.

Destroy target creature. Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Return target creature card from your graveyard to your hand. If you cast Lift Weary Heads from Rest from the graveyard, put it onto the battlefield instead.
Reconstruct {6}{B}{B} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

Whenever you gain life for the first time each turn, each opponent loses 2 life.