msem-instigator

Flying
Whenever Acabo, the Fabled Falcon attacks, you choose how up to one target creature an opponent controls blocks this turn.

Flying
When Arbiter of Silence enters, exile all other creatures until Arbiter of Silence leaves the battlefield. (They return to the battlefield under their owners' control.)

Flying
Concord — When Archangel of Accord enters, if there are four or more card types among permanents you control, destroy all other creatures.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever a nontoken creature you control enters, you may pay {1}{W}. If you do, create a 1/1 white Bird creature token with flying.

Ayala, Shrouded Shepherd can't attack or block unless your life total is greater than or equal to your starting life total.
Lifelink, indestructible
Whenever a creature attacks you or a planeswalker you control, you may pay {2}. If you do, create a 1/1 white Spirit creature token with lifelink blocking that creature.

Lifelink
Whenever Bjarndyr Sergeant attacks, other creatures you control get +1/+1 and gain lifelink until end of turn.

Vigilance
This spell costs {1} less to cast for each +1/+1 counter among creatures you control.

Vigilance, reach
Deploy 5 (As this enters, you may tap any number of other creatures you control with total power 5 or more.)
When Earthly Principality enters deployed, your life total becomes equal to your starting life total plus 5.

Flying, vigilance, lifelink
Embodiment of Law enters with an indestructible counter on it.
{5}{W}{W}, Remove an indestructible counter from Embodiment of Law: For each permanent type, exile up to one permanent of that type.

Flying
Whenever Empyrean Griffin attacks, up to one target creature voyages. (If it isn't blocking or targeted by another spell or ability, it phases out.)
Permanents your opponents control can't phase in.

Flying, lifelink

Flying, first strike, lifelink

Flying
Whenever you cast a creature spell, creatures you control get +1/+1 until end of turn.
Whenever you cast a noncreature spell, create a 2/2 red and white Cat Knight creature token.

Colossal 5—{8}{W}{W} (You may cast this for its colossal cost to have it enter with five +1/+1 counters; or pay {8}{W}{W} as a sorcery: Put five +1/+1 counters on it if it has none.)
Ward {5}
When Hekaton Dismantler's colossal ability puts one or more counters on it, tap each creature you don't control. Those creatures don't untap during their controller's next 100 untap steps.

Flying, prowess
If you would draw a card, scry 1, then draw a card instead.
Whenever an opponent casts a spell, if it's not their turn, draw a card.

Flying
Whenever Heroes of Wars Past attacks, attacking Human creatures get +1/+1 and gain flying until end of turn.

First strike, vigilance
Partner with Commander Hyctaleon (When this creature enters, target player may put Commander Hyctaleon into their hand from their library, then shuffle.)
At the beginning of your upkeep, you may search your library for a Soldier card, reveal it, put it into your hand, then shuffle.

Flying
When Imposing Sphinx enters, exile target nonland permanent an opponent controls until Imposing Sphinx leaves the battlefield.
At the beginning of your end step, if you gained life this turn, you may exile Imposing Sphinx, then return it to the battlefield under your control.

First strike
Mauling Mother gets +1/+1 for each other creature you control.

Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Vehicle becomes an artifact creature until end of turn.)

Flying, vigilance
Orzhov Benefactor can't attack or block unless you pay {1} for each debt counter on it.
At the beginning of your upkeep, put a debt counter on Orzhov Benefactor.
{2}: Remove a debt counter from Orzhov Benefactor.

Flying
Whenever a creature you control attacks alone, choose one —
• Exile target creature with power less than that creature's power.
• Put two +1/+1 counters on that creature.
• That creature gains first strike and lifelink until end of turn. Untap it.

Flying
Whenever a creature you don't control deals damage, its controller sacrifices it unless that player pays {2}.

Vigilance
When Scion of Storms enters, create a 2/2 white Elemental creature token with flying.
Whenever a Plains you control enters, you may aetherize Scion of Storms. (To aetherize, create a token that's a copy of it, then exile that token.)

Flying, vigilance, lifelink
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)