msem-instigator

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.)

Lifelink
Prevent all combat damage that would be dealt to embattled creatures you control. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

As Ancestral Facsimile enters, choose reality or illusion.
Foresight — Whenever you draw your second card each turn,
• Reality — Tap target creature.
• Illusion — Scry 2.

Flash
When Augmented Spawn enters, create a 1/1 blue Merfolk creature token for each Island you control.
{U}, Sacrifice a Merfolk: Augmented Spawn gains hexproof until end of turn.

Defender (This creature can't attack.)
Discard a card: Barge Engulfer can attack as though it didn't have defender until end of turn.

When this creature enters, put two -1/-1 counters on a creature you control.
When you put one or more -1/-1 counters on one or more creatures, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Concord — When Coral Bruiser enters, if there are four or more card types among permanents you control, put target creature you don't control into its owner's library third from the top.

This spell costs {1} less to cast for each tapped creature your opponents control.
{5}{U}: Evigian Titan can't be blocked this turn.

When Gulchdrinker Serpent enters, detain target permanent. (Until your next turn, that permanent can't attack or block and its activated abilities can't be activated.)