msem-instigator

Your opponents can't cast more than one spell each turn.
Identity — Lumi Orthodox gets +1/+2 as long as you control at least two other creatures that share a creature type with it.

Whenever a creature enters, you may tap it. If you do, put a +1/+1 counter on it.

Flash
Flying
When Lunar Emissary enters, exile another target creature you control until Lunar Emissary leaves the battlefield.

Flying
Crew 2
Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
As long as you're in a renaissance, Lunar Shachuan is an artifact creature.

When Lunar Vigil enters, draw a card, then scry 2.
If you would draw one or more cards, you may instead put a night counter on Lunar Vigil and draw that many cards minus one.
Sacrifice Lunar Vigil: Target player draws a card and adds {R} for each night counter on it.

Whenever one or more creatures in Luocha Mentor's pack attack, each creature in its pack gets +1/+0 until end of turn. (Two or more creatures you control with equal power are in a pack.)

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

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.

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

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.

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.)

Choose target creature you control. You may transform it if it's a Werewolf. Then it deals damage equal to its power to target creature you don't control. (The creature you control bites even if you don't transform it.)

Other Pirates and Rogues you control get +1/+0.
Whenever you attack with three or more Pirates and/or Rogues, tap target creature.

When Lysene enters, you may search your library for a card with foretell, reveal it, put it into your hand, then shuffle. The next card you foretell this turn costs {0} to foretell.
Whenever you foretell a card or cast a foretold spell, Pirates and Rogues you control get +1/+0 until end of turn. Up to one target Pirate or Rogue you control can't be blocked this turn.

Whenever you cast a spell, if it doesn't share a name with a permanent or a card in a graveyard, draw a card.

[+1]: Return a land you control to its owner's hand. Create a tapped colorless land token named Far-Off Lands with “{T}: Add one mana of any color.”
[–1]: Discard a card. Return to your hand a card from your graveyard that shares a color with that card or a color of mana it could produce.
[–3]: For each color pair, you may pay that mana. Create X X/X green and blue Elemental creature tokens, where X is the number of times you do.

First mate—Each nonland card in your starting deck is an instant or has flash. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Flash
When Mable enters, you gain 2 life and draw a card.

Haste
When Maddened Inferno leaves the battlefield, discard a card, then draw two cards.
Evoke {1}{R} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Players can't sacrifice creatures to cast spells or activate abilities unless that player sacrifices an additional creature. The same is true for discarding cards and paying life.

As an additional cost to cast this spell, discard a card.
Draw three cards, then discard a card.

Protection from sorceries
Whenever Magdel, Caller of Souls attacks, create a 1/1 white Spirit creature token with flying that's tapped and attacking for each storied permanent you control. Exile the tokens at end of combat. (Enchantments and legendary permanents are storied.)