msem-instigator

This spell costs {1} less to cast for each creature you control with power 4 or greater.
Reveal the top X cards of your library. You may cast any number of nonland cards with mana value X or less from among them without paying their mana costs. Put the rest into your graveyard.

Motivate 1 (When this creature enters, you may motivate target creature with less power than this by putting a +1/+1 counter on it.)
When Merthilios' Escort motivates a creature, that creature gains first strike until end of turn.

When Shokan Captain enters, you may search your library for an Equipment card, reveal it, shuffle, then put that card on top.
Art of war — At the beginning of your end step, if Shokan Captain dealt damage to an opponent this turn, put a +1/+1 counter on it.

Whenever you cast an enchantment spell, you may pay {W}. If you do, put a +1/+1 counter on target creature.

Creatures you control get +4/+4 and gain trample until end of turn.
Coalesce {8}{G}{G} (You may cast this from your graveyard for {8}{G}{G}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Trample

Destroy each artifact with mana value X or less, then create an Idol token for each artifact destroyed this way. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Reveal the top five cards of your library. Put an artifact or sorcery card from among them into your hand and the rest on the bottom of your library in any order.
Reconstruct {3}{R} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Create a 3/2 red creature token named Error with trample and haste. [Exile it at the beginning of the next end step.]

{T}: Add {C}.
{5}, {T}: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Dunesea Expanse enters tapped unless you control another Desert.
{T}: Add {W} or {U}.

Zombiecycling {1}{B} ({1}{B}, Discard this card: Search your library for a Zombie card, reveal it, and put it into your hand, then shuffle.)
Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the end step or if it would leave the battlefield. Unearth only as a sorcery.)

Return any number of target creature cards with total mana value X or less from your graveyard to the battlefield, where X is the number of cards in your graveyard. Exile Battle at the Boneyard.

Archive X (As this enters, shuffle the top X cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, create two 1/1 green Insect creature tokens.

Flying
When Cerulean Curtain Treasurer enters, audition for blue, then audition for blue again. (Create a 1/1 Construct Actor creature token, a Wizard Role giving 2/2 and prowess, or a Warlock Role giving 2/1 and flying. Roles replace older ones.)

Fiendish Yaoguai can't block.
Scavenge {5}{B} ({5}{B}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Counter target spell.
You may draw four cards. If you do, skip your next turn.

When Leech-Ridden Corpse dies, each opponent loses 1 life and you gain 1 life.

Enchant creature
When this enchantment enters, surveil 2.
Enchanted creature gets +2/+2 and has lifelink.

Target opponent reveals their hand. You choose an instant or sorcery card from it or a card from their graveyard. Exile that card.

Whenever you draw a card, put a +1/+1 counter on Ontarachie Curio.
{T}, Remove a +1/+1 counter from Ontarachie Curio: Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”
{1}{G}: Ontarachie Curio becomes a green 2/1 Dryad creature until end of turn. (It's no longer an artifact.)

This spell costs {1} less to cast for each card you've discarded this turn.
Draw three cards.

When you unveil Tempest Termagant, you may put target land on top of its owner's library.

Return target creature to its owner's hand.
Kindle 1—{U} ({U}, Exile this card from your graveyard: Create a 1/1 colorless Elemental creature token. Kindle only as a sorcery.)

This spell has flash as long as you control a permanent with flash.
Put target nonland permanent on top of its owner's library.