msem-instigator

Lost Explorer has first strike as long as it's attacking.
{1}{B}, Exile Lost Explorer from your graveyard: Crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Target player discards two cards.

Put target artifact or enchantment with mana value less than or equal to the number of basic lands you control on the bottom of its owner's library.

Flying
Whenever Lower Stratosphere Destroyer blocks or becomes blocked by a creature with flying, it gets +2/+2 until end of turn.
Crew 2

Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)
{1}{R}, Remove a +1/+1 counter from Lt. Daisy Saxon: She deals 2 damage to target player or planeswalker.

Reach
Lupine Skygrazer enters with a +1/+1 counter on it if three or more colors of mana were spent to cast it.

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

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.

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.

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.)

This spell costs {X} less to cast, where X is the number of creatures you control.
Vigilance

When Malicious Growth enters and at the beginning of your upkeep, put two +1/+1 counters on target land you control.
{1}{G}: Target land you control becomes a 0/0 Elemental creature with haste and vigilance until end of turn. It's still a land.

{2}: Exile up to two target cards in a single graveyard. If two creature cards were exiled this way, create a 1/1 blue Elemental creature token with flying.

When Mana Rose enters, you gain 2 life and scry 2.
{1}, {T}: Add one mana of any color.

Manaflux Battery enters tapped.
{T}: Add {C}{C}.
{2}, {T}: Untap each other artifact you control.

Menace
Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)

Marin Polgek, Academy Heiress has hexproof as long as you control three or more enchantments.
{1}{W/U}{W/U}: Create a token that's a copy of target enchantment you control.

Whenever another creature you control dies, put a +1/+1 counter on Marshy Marauder.
When Marshy Marauder dies, create a 1/1 green Insect creature token for each counter on it.

Marshy Vista enters tapped.
{T}: Add {B} or {R}.
{1}, {T}: Add one mana of any color.

First strike
Whenever Martial Maestro attacks, other attacking creatures you control get +1/+0 until end of turn.

Whenever an artifact you control enters, Master of Munitions deals 1 damage to each opponent.

Choose five. You may choose the same mode more than once.
• Each opponent sacrifices a creature or planeswalker.
• You draw a card and you lose 1 life.
• Each opponent loses 2 life.
• Each opponent discards a card.

When Matron of Machines dies, put a +1/+1 counter on up to one target creature.
{3}{W}, Exile Matron of Machines from your graveyard: Create two 1/1 colorless Construct artifact creature tokens. Activate only as a sorcery.

When Meadow Songstress enters, conjure three cards named Meadow Songstress and shuffle them into your main library.
Whenever a nontoken creature you control enters, if it shares a name with one or more other creatures you control, draw a card.

Gain control of target creature with power X or less.