msem-instigator

Lifelink
If a creature or planeswalker would die, instead exile it and put a +1/+1 counter on Librarian of Whispers.

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.)

When Life's Harbinger dies, you may put a +1/+1 counter on target creature you control.
{T}: Add {G}.

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

{3}{G}: Put a +1/+1 counter on Lifecaller Dryad.

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.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

Whenever you activate a loyalty ability of a planeswalker, you gain 1 life.

Haste
At the beginning of each end step, if Lightning Ox dealt damage this turn, sacrifice it.

Whenever another artifact you control enters, put a +1/+1 counter on Lightsteel Enforcer.

Lightwalker has flying as long as it has a +1/+1 counter on it.

When Lilyreed Triton enters, create a white Aura enchantment token named Triton's Gift attached to target creature. The token has enchant creature and “Enchanted creature gets +1/+0 and can't be blocked by creatures with power 3 or greater.”

When Lisa, the Daughter enters, create Mother, a legendary 4/1 black Demon creature token with flying and “This creature can't block.”
If a source would deal damage to Lisa while you control a Demon creature, instead that damage is dealt to a Demon creature you control of your choice.

Whenever Little Kibo attacks, you may pay {W}{W}. If you do, transform it.

When Little Pig enters, if you control a land named Far-Off Lands, put two +1/+1 counters on it.

Living Broadcast can't block.
Whenever you cast a spell from exile, you may return Living Broadcast from your graveyard to your hand.

{2}{B}, Exile Lizhao's Soulblade from your graveyard: Return target creature card from your graveyard to your hand. Activate only as a sorcery.

Each other creature you control that's an Elf or a Warrior gets +1/+1.
{2}, Sacrifice Llanowar Exemplar: Creatures you control gain indestructible until end of turn.

Menace

Flying
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

Lone Hunter has indestructible as long as it has attacked alone this turn.
Whenever Lone Hunter becomes the target of a spell or ability you control, if it cost one or more mana to cast or activate, you may pay {1}. If you do, draw a card.

When Lone Stranger enters, if you control no other creatures, create two 1/1 colorless Spirit creature tokens.

Menace
Lonely Devil can't attack or block alone.

{2}{G}: Put a +1/+1 counter on Lonesome Ravager.
Ride {G} ({G}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)