msem-instigator

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.

Menace
Whenever one or more creature cards leave your graveyard, put a +1/+1 counter on Mausoleum Resident. It gains lifelink until end of turn.

Reach
When Mawdryk's Harrier enters, look at the top six cards of your library. You may put an Elf card with lesser mana value from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Other Elves you control get +1/+1.

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.

{W}{B}, Pay X life: Return target creature card with mana value X from your graveyard to the battlefield with a finality counter on it. Activate only as a sorcery and only once each turn.
{W}{B}, Pay 3 life: Return Mehr's Last Captain from your graveyard to the battlefield with a finality counter on it.

Whenever Mei's Student deals combat damage to a player, fateseal 1, then scry 1. (Look at the top card of an opponent's library, then you may put it on the bottom.)

When Meletis Oracle enters, scry 1, then draw a card.

Heroic — Whenever you cast a spell that targets Meletis Stargazer, scry 2.
{T}: Look at the top card of your library. If it's a permanent card with mana value 3 or less, you may reveal it and put it into your hand.

Whenever Memory of Fatalism dies or you cast a noncreature spell, each opponent loses 2 life and you gain 2 life.
{4}: Put Memory of Fatalism from your graveyard on top of your library.

When Mental Supremacist enters, choose target creature you don't control. That creature has base power and toughness 1/1 and loses all abilities for as long as you control Mental Supremacist.

Whenever another creature with power 4 or greater you control enters, you may draw a card.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Mercenary Coercer deals combat damage to a player, that player discards a card.

Deathtouch
Sacrifice a creature: Target player mills two cards.

Whenever Merchant of Flesh or another creature you control dies, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
{B}, Sacrifice two Treasures: Each opponent sacrifices a creature.

{2}{G/U}{G/U}, {T}: Untap each non-Lizard permanent you control.

Flying, haste
{X}{R}{R}, Exile an instant or sorcery card with mana value X from your graveyard: Return Merkurio's Familiar from your graveyard to the battlefield. It gets +X/+0 until end of turn.

Whenever Merrow Legendmaker attacks, look at the top five cards of your library. You may reveal an Aura, Aurashaper, or Equipment card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Flying
When Messenger of the Heavens enters, surveil 1.
Whenever Messenger of the Heavens deals combat damage to a player, exile any number of target creatures in its pack, then return them to the battlefield under your control. (Two or more creatures you control with equal power are in a pack.)

Whenever another artifact you control enters, put a +1/+1 counter on Metalwork Machinist.

{3}{R}: Attacking creatures you control get +1/+0 until end of turn.

Embellish {4}{W} (If you cast this spell for {4}{W}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)
When Meticulous Mechanist enters, scry 1.

Engage (This creature must be blocked each combat if able.)
{R}: Mettlesome Watchkeeper gets +1/+0 until end of turn.

Flash
Wanderlust — When Microzoologist enters, search your library for a creature card with mana value 1. If you control four or more differently named lands, you may search for a creature card with mana value 3 or less instead. Reveal that card, put it into your hand, then shuffle.

Vigilance
When Mid-Autumn Celebrants enters, create a 2/2 white Panda Bear Monk creature token with vigilance.

{B}, Sacrifice another creature: Surveil 1.