msem-instigator

Whenever you cast a spell, for each of that spell's colors, create a 1/1 Scout creature token that's all colors.

Look at the top three cards of target player's library. Put one back and exile the rest.
Coalesce {5}{U} (You may cast this from your graveyard for {5}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Whenever Lurk at Vision's Edge attacks, defending player exiles the top five cards of their library.

When Lurking Angler enters, if seven or more cards are in your graveyard, draw a card. Otherwise, mill two cards.

Put a +1/+1 counter on target creature. It can't be blocked this turn.(Cast a copy of this spell once while this creature is on the battlefield.)

Menagerie — When Lurking Feralynx enters, if there are five or more creature types among creatures you control, you may search your library for a card named Lurking Feralynx, reveal it, put it into your hand, then shuffle.

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.)
Hexproof

Concord — Lurking Lahasia has first strike and lifelink as long as there are four or more card types among permanents you control.

Destroy target creature that was dealt damage this turn, then create a 3/2 black Mutant Horror creature token.

Target creature gets +3/+3 and gains haste until end of turn.

At the beginning of your end step, any number of target players mill three cards.
{5}{U/B}, {T}: You may cast target instant or sorcery card from an opponent's graveyard without paying its mana cost. Activate only as a sorcery.

Lush Coast enters tapped.
{T}: Add {G} or {U}.
{1}, {T}: Add one mana of any color.

Enchant land
Enchanted land has “{T}: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.”

({T}: Add {G} or {U}.)
Lush Oasis enters tapped unless you control a basic Forest or a basic Island.

Lush Outcrop enters tapped unless another player controls a land that could produce {R} or {G}.
{T}: Add {R} or {G}.

Lush Outskirts enters tapped.
{T}: Add {G} or {U}.
{3}{G}{U}: Until end of turn, Lush Outskirts becomes a 5/7 green and blue Plant creature with with ward {3} and “Whenever this creature attacks or blocks, torment yourself.” It's still a land. (To torment yourself, lose 3 life unless you discard a card or sacrifice a nonland permanent.)

When Lust for Life enters, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Augmented — Whenever a creature you control enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, you may sacrifice Lust for Life. If you do, create a token that's a copy of that creature.

Enchant creature
Enchanted creature has distorted. (It can be blocked by tapped creatures but not untapped creatures.)
{1}{B}: Enchanted creature can't block this turn.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
{1}{U}, Discard Lusterwing Owl: Return target enchantment to its owner's hand.

When Lustrebloom Diviner enters, create a Treasure token.
At the beginning of each end step, if you spent three or more colors of mana to cast spells this turn, you gain 3 life. If you spent {W}{U}{B}{R}{G}, draw a card.

Flying
When Lustrous Devout enters, choose one —
• Put a +1/+1 counter on Lustrous Devout.
• Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Flying
Prismatic — Whenever you cast a multicolored spell, scry 1.

Whenever Lute Tickler attacks, you may goad target creature defending player controls. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

When Lysander Jal enters, create a token that's a copy of another target noncreature permanent you control.
Whenever you cast a spell from your graveyard, return target permanent card from your graveyard to your hand.

Flying
Whenever another creature you control enters, you may search your library for an instant or sorcery card with the same mana value as that creature, reveal it, put it into your hand, then shuffle.

Attacking Pirates and Rogues you control get +1/+0.
{2}{U}: Tap target creature an opponent controls.