msem-instigator

Trample, haste
Erratic (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)
At the beginning of the end step, sacrifice Purgator of Storms.

Codex — Unraveling; Unraveling; Unrelenting; Unrelenting; Mindrip; Swipe Secrets. (As this enters, conjure its contents into a shuffled face-up additional library.)
Flash
When Mei's Collection enters, draw a card from its codex.

Sundappled Scrub enters tapped unless you control another Desert.
{T}: Add {G} or {W}.

Stormcharged Pyre enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

When Tessellated Orb enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.
When Tessellated Orb dies, draw a card.

Whenever a nontoken creature you control enters, if it shares no creature types with other creatures you control, draw a card.

Radiant Vistas enters tapped.
{T}: Add {W} or {U}.
{W}{U}, {T}, Sacrifice Radiant Vistas: Conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Return target creature card from your graveyard to the battlefield. Then up to one target opponent sacrifices a creature if you control an Angel, Demon, Faerie, or Spirit.

{2}{W}, Sacrifice Gleamhorn Elk: Destroy target artifact or enchantment.

When Chiheisen, Terrace of Serenity enters, draw a card, then choose a creature card name.
Spells you cast with the chosen name cost {2} less to cast.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever Protective Patron extorts a creature spell, that creature gains indestructible until your next turn.

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever you attack, add a quest counter.
1, 2 — Untap target creature or land you control.
3 — Create two 2/2 green Wolf creature tokens.
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Flying
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)

When Treasure Hoard enters, create a 2/2 blue Rogue creature token.
{2}{R}, Tap an untapped creature you control, Sacrifice Treasure Hoard: Create two Treasure tokens. (They're artifacts with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Each player loses 3 life, then discards a card, then sacrifices a creature, an enchantment, a land, a planeswalker and a token. Then exile all graveyards.

As an additional cost to cast this spell, discard a nonland card.
All creatures get -X/-X until end of turn, where X is the discarded card's mana value.

This spell can't be countered.
You can't lose the game this turn and your opponents can't win the game this turn. Until end of turn, damage that would reduce your life total to less than 1 reduces it to 1 instead.

When Ancestral Council enters, search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

You may reveal the second card you draw each turn as you draw it. When you do, create a 2/2 blue Avatar Wizard creature token with prowess if it's a creature card. If it's a land card, create a Treasure token. If it's a noncreature, nonland card, Steward of Second Sphere can't be blocked this turn.
{3}{W/U}{W/U}: Scry 2.

You may choose not to untap Arden, Mirrormage during your untap step.
Whenever Arden becomes untapped or leaves the battlefield, sacrifice all tokens created with it.
{3}{U}, {T}: Create a token that's a copy of another creature on the battlefield.

{T}: Hotblooded Sorcerer deals 1 damage to target player or planeswalker.
Attain {3}{R} ({3}{R}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Each opponent discards all the cards in their hand, then draws that many cards. You discard your hand, then draw cards equal to the number of cards your opponents drew this turn.

Players can't gain life.
At the beginning of each player's upkeep, if that player has 10 or less life, they lose 1 life.

When Wretched Spawn enters, you may return target permanent to its owner's hand. If you do, that player discards a card.
Unearth {4}{U}{B} ({4}{U}{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.)

Overwhelming Fusillade deals 4 damage divided as you choose among any number of targets.
If you control a creature with power 4 or greater, Overwhelming Fusillade deals 2 damage to each opponent.