msem-instigator

Double strike, vigilance
Whenever Major Benjamin Stout enters, attacks, or dies, recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

[+1]: Exile up to one target tapped creature.
[–2]: Create a 4/4 white Angel creature token with flying.
[–3]: Destroy all creatures. You gain 1 life for each creature destroyed this way.
[–7]: You get an emblem with “At the beginning of each end step, you gain life equal to twice the life you've lost this turn.”

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Master of Ancient Ways mentors a creature, that creature gains double strike until end of turn.

When Master of Marble Row enters, choose one —
• Create a colorless Monument artifact token with “Creatures you control get +1/+1.”
• Create a white Cloister enchantment token with “When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.”

Whenever Queen Hannaru enters or attacks, put a +1/+1 counter on another target creature you control.
At the beginning of your upkeep, if there are four or more +1/+1 counters among creatures you control, you may transform Queen Hannaru.

Indestructible
Whenever Hannaru the Conqueror attacks, put a +1/+1 counter on each creature you control.

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.)

[+1]: Create two 1/1 white Warrior creature tokens. You gain 2 life.
[–2]: Destroy each creature with the greatest power or tied for the greatest power among creatures on the battlefield.
[–5]: Creatures you control get +X/+X and gain lifelink until end of turn, where X is the number of creatures you control.

Destroy all creatures.

Flying
Sire of Empires gets +1/+1 as long as you control another creature, has lifelink as long as you control an enchantment, and has vigilance as long as you control an artifact.

When Strayseeker Ranger enters, search your library for a creature card with mana value 2 or less, reveal it, put it into your hand, then shuffle.
Recite {W}{W} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

First strike
When Sworn Cohort dies, you may search your library for a legendary card, reveal it, put it into your hand, then shuffle.

Choose one —
• Exile target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.
• Until end of turn, if a creature would enter and it wasn't cast, exile it instead.
Flashback {1}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

(As this Discovery enters and after your draw step, add a progress counter. Stop after you've discovered.)
I, II — Look at the top five cards of your library. Put up to one creature card with mana value 2 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Discovery — At the beginning of combat on your turn, tap target creature an opponent controls.

Flash
Flying
When Turela, Defiant Angel enters, exile all other creatures you control. Return them to the battlefield under their owner's control at the beginning of the next end step.

Motivate 1 (When this creature enters, you may motivate target creature with less power than this by putting a +1/+1 counter on it.)
{2}{W}{W}: Exile Valtrian Cavalier, then return it to the battlefield under your control.

Flying, lifelink
At the beginning of each end step, if you gained 3 or more life this turn, choose one —
• Put a +1/+1 counter on Waxing Angel.
• Exile target artifact or enchantment.

Flash
When Aethermancer's Familiar enters, at the beginning of the next end step, you may aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

You may put a creature or Revelation card from your hand onto the battlefield. Exile that permanent if it would leave the battlefield. If it's a Revelation, it enters as a Horror creature.
Coalesce {7}{U}{U} (You may cast this from your graveyard for {7}{U}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

You may have Blurry Counterpart enter as a copy of any creature on the battlefield.
Mirage {1}{U} (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.)

[+1]: Draw two cards.
[–1]: Until your next turn, Director Amitai Eliahu gains “Other nonland permanents lose all abilities.”
[–3]: You may discard a card. If you do, you may cast a spell that shares a color with that card without paying its mana cost.
[–9]: Until end of turn, play with your library revealed. You may cast spells from your library this turn.

Flash
When Duplicated Dismantler enters, if you cast another spell this turn, return target spell to its owner's hand.

If you would draw one or more cards, instead you may draw that many cards plus one, then discard a card.
As long as ten or more cards are in your graveyard, noncreature spells you cast cost {1} less to cast.

Flash
When Emissary of Dark Tides enters, you may return target noncreature spell or tapped creature to its owner's hand.

Choose X. You may choose the same mode more than once.
• Counter target spell unless its controller pays {3}.
• Return target nonland permanent to its owner's hand.
• Target player draws a card.