msem-instigator

Exile target creature. That creature's controller reveals cards from the top of their library until they reveal a creature card. That player puts that card onto the battlefield, then shuffles the rest into their library. If you own that card, it enters with an additional X +1/+1 counters on it, where X is its power.

Monstrous Amalgam gets +X/+X, where X is the number of creature cards in your graveyard.
{B}, Reappropriate: Put a +1/+1 counter on Monstrous Amalgam. Activate only once each turn. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)

Vanguard — Whenever a creature you control attacks alone, that creature gets +3/+0 until end of turn.

Assault {2}{R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Monstrous Hila assaults, it deals 3 damage to any target.

When Monstrous Hunter enters, destroy up to one target creature.
At the beginning of each end step, if a creature died this turn, you draw a card and you lose 1 life.

First strike

Reach
At the beginning of your end step, if you created one or more creature tokens this turn, create a 1/2 green Spider creature token with reach.

{5}, {T}, Exile a creature you control: Exile target creature.

Whenever a creature you control enters, put a devotion counter on Monument of the Masses.
At the beginning of your upkeep, if Monument of the Masses has thirty-five or more devotion counters on it, you win the game.

Monumental Siege deals 5 damage divided as you choose among any number of targets. Whenever a creature dealt damage this way this turn dies, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Lifelink
At the beginning of your end step, you gain 1 life if you gained life this turn, and each opponent that lost life this turn loses 1 life.

Whenever a creature dealt damage by Mooncursed Howler this turn dies, create a 2/2 red Werewolf creature token with first strike.

Whenever you gain life, you may put target creature or planeswalker card from your graveyard on top of your library.

{1}{B}, Pay 2 life: Moonlight Butcher gains menace until end of turn.

As Moonlight Sanctum enters, choose Waxing or Waning.
• Waxing — At the beginning of your upkeep, you gain 1 life for each enchantment you control.
• Waning — Nonenchantment spells cost {1} more to cast.

Moonlight Stag has vigilance as long as it has a +1/+1 counter on it.

First strike
Other Harpies you control get +1/+1 and have first strike.
Whenever a Harpy you control dies, put a +1/+1 counter on Moonlight Stalker.

Flying
When Moonlit Charmer enters, tap target artifact or creature. It doesn't untap during its controller's next untap step.

Flash
Whenever Moonlit Hunter enters or you cast a noncreature spell, tap target permanent and untap a second target permanent.

Whenever Moonlit Lurker blocks, put a +1/+1 counter on it.

When Moonshadow Remnant enters, destroy target tapped creature.
Mirage {3}{W}{W} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

At the beginning of your end step, for each permanent with exactly one counter on it, you may choose one —
• Remove all counters from that permanent.
• Choose a kind of counter on that permanent. Put another counter of that kind on that permanent.

Flying
{1}{U}: Reveal the top card of your library. Moonwing Watcher's base power becomes equal to that card's mana value.
Prophecy {U} (Once each turn, you may exile a card with prophecy as you reveal it. When you do, you may cast it for its prophecy cost as long as it's exiled.)

Trample
When Moranai Outriders enters, if it's not a token, create a token that's a copy of it, except it has no mana cost.

Whenever you activate an ability of a creature that isn't a mana ability, Moranai Tracker gets +1/+1 until end of turn.