msem-instigator

Haste (This creature can attack and {T} as soon as it comes under your control.)
Double strike (This creature deals both first-strike and regular combat damage.)

Whenever a non-Serf creature you control enters, create a 0/1 black Serf creature token.
Sacrifice a Serf: Target creature you control gets +0/+1 until end of turn.

Flying, vigilance
When Manafly enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Flying
Whenever you attack, create two 1/1 white Human creature tokens that are tapped and attacking. Creatures you control get +1/+1 until end of turn.
Fleeting {2}{W}{W} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Civilized — When Marble Row Healer enters, if you control an artifact, a creature, and an enchantment, you gain 4 life.

Flying, lifelink
Your opponents can't search libraries.
{B}, Pay 2 life, Discard a card: Search your library for a card, then shuffle and put that card on top.

{1}{G}: Marrow Gorger must be blocked this turn if able.

Improve {B} ({B}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever a nontoken creature you control dies, if it was embattled, you may pay {B}. If you do, create a 2/2 black Zombie creature token. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Renown 1
When Marshal Jin Guiying becomes renowned, you may search your library for an artifact or enchantment card, reveal it, put it into your hand, then shuffle.

Flash
When Master Echomage enters, you may cast target instant or sorcery card from your graveyard with mana value X or less without paying its mana cost, where X is the number of Wizards you control. Exile that card instead of putting it into your graveyard as it resolves.

Creatures you control attacking cause abilities of that creature to trigger as though it entered.
{2}{R}{W}: Target creature gains vigilance and haste until end of turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Whenever an Actor you control becomes untapped, you may discard a card. If you do, draw a card.

Menace
Foresight — Whenever you draw your second card each turn, search your library for a card, put it into your hand, then shuffle.

Instant and sorcery spells you cast cost {1} less to cast.
{U}, {T}, Exile three instant and/or sorcery cards from your graveyard: Draw a card.

You may choose not to untap Master of Minds during your untap step.
{T}: Gain control of target creature with mana value X or less for as long as Master of Minds remains tapped, where X is the number of Islands you control.

You may activate equip abilities any time you could cast an instant if you pay an additional {1} to activate them.
Armed — Equipped creatures you control get +1/+1 as long as Master of Steel is equipped.

When Master of the Abyss enters, draw two cards, then discard a card.
{2}{U}{U}, {T}, Discard two cards: Create an X/X black Horror creature token, where X is the number of cards in your graveyard.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Mausoleum Revenant deals damage to a player, create a 2/2 black Zombie creature token.

Poisonous 3 (Whenever this creature deals combat damage to a player, that player gets three poison counters.)
At the beginning of your upkeep, if an opponent is poisoned, you may have Mautakesh Strangler fight target creature you don't control.

As long as you control another white creature, Mavisa's Familar has lifelink. The same is true for blue and flying, black and deathtouch, and red and trample.

Menace
Landfall — Whenever a land you control enters, Mawdryk's Elite gets +1/+0 and gains deathtouch until end of turn.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
Recursive — As long as Mayar, Nullcrowned is a Curse, they have all nonrecursive abilities of other Curses and creatures with breach you control.
Pay 3 life: Target enchantment creature gains haste and menace until end of turn.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)

Lifelink, menace