msem-instigator

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

Enchant opponent
Whenever a creature enters under enchanted player's control, that creature gets -0/-2 until end of turn unless that player pays 2 life.

As Mercantile Accords enters, choose a number.
Whenever an opponent casts a spell with the chosen mana value, you draw a card and create a Treasure token.

At the beginning of your upkeep, draw a card.
At the beginning of your end step, discard a card.

Flying, vigilance
Prevent all damage Merciful Yuroda would deal to creatures.

When Merciless Blackguard enters, each player sacrifices a creature. For each creature token sacrificed this way, you may create a Treasure token.

Merciless Champion can't block unless you control another Knight or Soldier.

Menace
Ferocious — Whenever Merciless Xun Huang attacks, if you control a creature with power 4 or greater, defending player sacrifices a permanent.

This spell can't be countered.
Whenever Meren, Bane of the Cairns attacks, exile target creature card from your graveyard. You may cast that card for as long as it remains exiled by sacrificing a creature in addition to paying its other costs.

Whenever Merfolk Vandal deals combat damage to a player, you may pay {U}. If you do, transform it.

[+1]: Merkurio deals 2 damage to target player or planeswalker. That player or that planeswalker's controller may draw a card.
[–2]: The next instant or sorcery spell you cast this turn costs {U}{R} less to cast. This effect reduces only the amount of colored mana you pay.
[–7]: You get an emblem with “Each instant and sorcery card you own has reverberate {X}, where X is its mana value.” (When you cast a spell, copy it if you paid its reverberate cost. You may choose new targets for the copy.)

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Prowess
When Merkurio's Opus enters, if it was kicked, draw two cards, then discard two cards.

Counter target spell unless its controller pays {2} for each Wizard on the battlefield.

Return target nonland permanent to its owner's hand.
Reprise {2}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Meteor Volley deals 3 damage to each creature.
Reprise {4}{R}{R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

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.

Enchant creature or artifact
When Meticulous Process enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
Enchanted permanent doesn't untap during its controller's untap step.

Whenever a land you control enters, crystallize.
{10}: Shuffle any number of other permanents you control into their owner's library. Mill that many cards. Put all permanent cards milled this way onto the battlefield. Activate only during your turn and only once each turn.

Mianju enters with your choice of a menace or +1/+1 counter on them.
Whenever two or more creatures in Mianju's pack attack, mill three cards, then return a creature card from your graveyard to your hand. (Two or more creatures you control with equal power are in a pack.)

Create a 2/2 blue Jellyfish enchantment creature token with flying.
Flashback {4}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

When Miede-District Alchemist enters, add {R}{R}{R}.
Paranoia {1}{R} (You may cast this spell for its paranoia cost when a permanent you control leaves the battlefield.)

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
{1}{R}: Mieng gains flying until end of turn.
Whenever Mieng attacks, create a 4/4 red Dragon creature token with flying that's tapped and attacking. Exile that token at end of combat unless you're in a renaissance.

Reveal the bottom two cards of your library. You may put one of those cards into your hand. If you do, target creature gets +X/+X until end of turn, where X is that card's mana value.

Until end of turn, target creature gains double strike and damage dealt by it can't be prevented.
Fuse (You may cast one or both halves of this card from your hand.)

When Militant Arms enters, create a 1/1 white Human creature token, then attach Militant Arms to it.
Equipped creature gets +2/+1.
Equip {3}