msem-instigator

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
Once during each of your turns, you may cast a spell with mana value 3 or less that targets a cursed opponent or a permanent a cursed opponent controls by paying life equal to its mana value rather than its mana cost.

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

When Left for Dead enters, create four 1/1 red Human Survivor creature tokens. Those tokens gain haste until end of turn.
At the beginning of your end step, sacrifice a Survivor. If you do, draw a card. Then if you control no Survivors, sacrifice Left for Dead.

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.

Enchant creature
Embody (Enchanted creature is a copy of this card except for its types.)
As long as Legend of the Weary is tapped, creatures you don't control get -1/-1.

{B}, {T}, Discard a card: Create a 1/1 black Skeleton creature token.
{B}, {T}, Sacrifice a creature: Put a +1/+1 counter on each Skeleton you control.

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.”)

Flying
At the beginning of your end step, put a +1/+1 counter on Lepidopteradator if you're horrific. Otherwise, sacrifice it. (You're horrific as long as you've sacrificed a permanent or discarded a card this turn.)

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.

When Leyline Invoker enters and at the beginning of your upkeep, you may mill two cards.
{5}{B}, {T}, Sacrifice Leyline Invoker: Return target creature card from your graveyard to the battlefield. This ability costs {1} less to activate for each creature card in your graveyard.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Lifelink
When Leyran-Pack Outcast attacks, if it's alpha, each player sacrifices a creature.

When Lich's Grimoire enters, create a 2/2 black Zombie creature token.
{2}{B}, {T}: Target opponent loses 1 life. Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Creatures you don't control get -1/-1.

Flying
Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Liege of Luxury desecrates a permanent, target player reveals their hand. You choose a card from it and exile it. You may cast that card for as long as it remains exiled, and you may spend mana as though it were mana of any type to cast that spell.

Menace
Whenever Lieshi Pariah deals combat damage, you lose that much life unless it's in a pack. (Two or more creatures you control with equal power are in a pack.)

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

Whenever a +1/+1 counter is put on Lifeblood Leecher, target creature an opponent controls gets -1/-1 until end of turn.

Pay 2 life: Lifecraft Aberration gains indestructible until end of turn.
Pay 3 life: Lifecraft Aberration gets +1/+1 until end of turn.

When Lifegorging Aberration enters, each opponent loses X life, where X is the number of Zombies you control. You gain life equal to the life lost this way.

When Lifespark Alchemist enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Whenever Lifespark Alchemist or another creature dies, each opponent loses 1 life.

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.

{T}, Pay 1 life: Add {B}.
{7}{B}{B}, Exile Ligos, Shadow's Source from your hand: Destroy all creatures you don't control. They can't be regenerated.