msem-instigator

When Lotus Feaster enters, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

{T}, Mill a card: Add {B} or {G}.
Once each turn, when a creature you control dies or a creature card is put into your graveyard from anywhere other than the battlefield, each opponent loses 1 life.

When Lotus-Scarred Luocha enters, create a 2/1 black Spirit creature token with “This creature can't block.”
Whenever a creature in Lotus-Scarred Luocha's pack dies, each opponent loses 2 life and you gain 2 life. (Two or more creatures you control with equal power are in a pack.)

Vigilance
Whenever Lowly Cataphract and at least two other creatures attack, put a +1/+1 counter on Lowly Cataphract.
Surpass {5}{W} ({5}{W}: Transform this. This costs {1} less to activate for each counter on
it. Activate only as a sorcery.)

Ride {2}{W} ({2}{W}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

When Lumenbay Jailer enters, you may exile target nonartifact creature until Lumenbay Jailer leaves the battlefield.

Changeling (This card is every creature type.)
{1}: Another target creature you control gains the creature type of your choice until end of turn.
{1}: Change the text of another target creature you control by replacing all instances of one creature type with the creature type of your choice until end of turn.

Flash (You may cast this spell any time you could cast an instant.)
{2}{G}: Luminescent Croaker gains indestructible until end of turn.

Whenever Luna enters or phases in, each player loses 1 life.
Whenever a player casts a spell or a creature attacks, Luna phases out.

{T}: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
At the beginning of combat on your turn, you may exile a creature card from your graveyard. When you do, target creature with the same power as the exiled card can't be blocked this turn.

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

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.)

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.

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

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

Spells you cast from anywhere other than your hand cost {1} less to cast.
At the beginning of combat on your turn, another target Pirate or Rogue you control gets +X/+0 and gains haste until end of turn, where X is the number of noncreature spells you've cast this turn. That creature can't be blocked this turn.

When Maaru, Tomb Guardian enters, create three Treasure tokens.
Each Treasure you control is an artifact creature with power and toughness each equal to the number of Treasures you control.

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

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.

Flying
Whenever Macabre Blademaster attacks, another target creature in its pack gains lifelink and deathtouch until end of turn. (Two or more creatures you control with equal power are in a pack.)

If Madame Beatrice would leave the battlefield, exile her instead.
Whenever one or more creatures you control deal combat damage to a player, that player reveals their hand. You may cast a card from their hand without paying its mana cost.

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.)

Whenever an opponent activates an ability of a permanent, if it isn't a mana ability, you gain 1 life and create a Gold token. (It's an artifact with “Sacrifice this artifact: Add one mana of any color.”)

Menace
Stampede — Whenever Maelstrom Slicer and a creature with greater power attack, exile the top three cards of your library. You may play those cards until end of turn.

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.)