msem-instigator

Deathtouch
Whenever an opponent casts a noncreature spell, draw a card.

Mine Delver has first strike as long as it's embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Whenever Ming Fleet Privateer attacks, put a menace counter on target creature in its pack. (Two or more creatures you control with equal power are in a pack.)

When Mining Rover Manager enters, create a 1/1 colorless Servo artifact creature token.

Colossal 3—{6}{R} (You may cast this for its colossal cost to have it enter with three +1/+1 counters; or pay {6}{R} as a sorcery: Put three +1/+1 counters on it if it has none.)

{1}{R}, {T}: Target creature gains shimmer until end of turn. (Whenever it attacks this turn, create a tapped and attacking token that's a copy of it. Exile that token at the beginning of the end step.)

Reach
Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Other Elementals you control get +1/+1 as long as Miroran Skycatcher has a +1/+1 counter on it.

Whenever you cast a green or blue spell, create a 1/1 green and blue Elemental creature token.
Each Elemental you control enters with an additional +1/+1 counter on it.

Prowess

Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, put a +1/+1 counter on Mirrorcast Battlemage.
Remove three +1/+1 counters from Mirrorcast Battlemage: Copy target instant or sorcery spell you control. You may choose new targets for the copy. Activate only once each turn.

Flash
Whenever Mischievous Capuchin or another Monk you control enters, tap target creature you don't control. If it was already tapped, it doesn't untap during its controller's next untap step.

Noncreature spells your opponents cast cost {1} more to cast.
Unveil {2}{W}{U} ({2}{W}{U}: Transform this. Unveil only as a sorcery.)

Other creatures you control get +2/+0 and have menace.
Whenever another creature you control dies, if it wasn't sacrificed, sacrifice a creature.

Dragon spells you cast cost {1} less to cast.
{1}{R}: Until end of turn, Miyoga Dragonsoul becomes a 2/2 red Dragon creature with flying and “{R}: Miyoga Dragonsoul gets +1/+0 until end of turn.” Activate only as a sorcery.

Flying, haste
Miyoga Firebird attacks each combat if able.
Whenever you cast your third instant or sorcery spell this turn, you may return Miyoga Firebird from your graveyard to the battlefield.

Haste
{1}: Exile Mizujutsu Master. Return it to the battlefield under its owner's control at the beginning of the next end step.

Ward—Pay 2 life.
Whenever another creature dies, put a hysteria counter on Mob of the End.
At the beginning of your first main phase, remove all hysteria counters from Mob of the End and add that much {R}.

Modular Mercenary gets +1/+0 and has first strike as long as you control a creature with a +1/+1 counter on it.

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Double strike
If this creature would deal noncombat damage, it deals double that damage instead.

Molting Abomination can't be blocked by creatures with power 2 or less.
Whenever Molting Abomination deals combat damage to a player or planeswalker, create a tapped 3/2 colorless Horror creature token. Put a stun counter on that token. (If a permanent with a stun counter would become untapped, remove one from it instead.)

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.)

First strike

Sacrifice Moonlight Agent: Blocking creatures gain first strike until end of turn.

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.