msem-instigator

Iron Warden enters with three -1/-1 counters on it.
When Iron Warden dies, you may distribute X -1/-1 counters among any number of target creatures, where X is the number of -1/-1 counters on Iron Warden.
{2}{R}: Put a -1/-1 counter on target creature.

Other Knights and Soldiers you control get +1/+0.
Cowards can't block Knights and Soldiers you control.
When Belmord Bloodcurdler enters, target creature an opponent controls becomes a Coward in addition to its other types. (This effect last indefinitely.)

Prowess
Whenever Knight-Academic attacks, scry 1.

At the beginning of your end step, choose any number of permanents and/or players, then give each another counter of each kind it already has.
[+1]: Scry 1. Add {U} or {R}.
[–X]: Exile the top X cards of your library. Until end of turn, you may play a card exiled with Trainee Karina Oblay.

[+2]: Each opponent loses 2 life. Scry 2.
[–3]: Return target creature to its owner's hand. That player discards a card.
[–6]: You get an emblem with “Whenever a player discards a card, you may cast it without paying its mana cost.”

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Exile target creature card from a graveyard. Create a token that's a copy of that creature, except it's a colorless artifact. (It's not a creature.)

{T}: Add {C}.
{2}, {T}: Draw a card. Activate only if you have no cards in hand.

Whenever Merciless Shieldbreaker enters or attacks, target opponent puts three rust counters on a permanent they control with no rust counters on it. That permanent gains “At the beginning of your upkeep, remove a rust counter from this permanent. Then if there are no rust counters on this permanent, sacrifice it and it deals 4 damage to you.”

Flying, trample
When Ashen Persecutor enters, target opponent reveals their hand. You choose a nonland card from it. That player discards that card and you gain life equal to its mana value.

Kicker {X} (You may pay an additional {X} as you cast this spell.)
When Korrinary Warcaller enters, if it was kicked, search your library for a Rebel permanent card with mana value X or less, put it onto the battlefield, then shuffle.

The Mythical Zhiwu enters with four +1/+1 counters on it.
{1}, Remove a +1/+1 counter from a creature you control: Target creature gets -1/-1 until end of turn. Activate only as a sorcery.
{1}, Remove a +1/+1 counter from a creature you control: Each opponent loses 1 life and you gain 1 life.

Primal—Reappropriate green. (During your turn, you may cast this spell by exiling two green cards from your hand and/or graveyard instead of playing a land.)
When Dovon's Masterwork enters, return target land card from your graveyard to the battlefield tapped.

When Blessed Spellroot dies, you gain 5 life.

{T}: Add {G} or {U}.
{T}, Sacrifice Sigil of Creation: Add {G}{U}.

{T}: Add {W} or {B}.
{T}, Sacrifice Sigil of Martyrdom: Add {W}{B}.

Entropic Inferno deals 5 damage divided as you choose among any number of targets. At the beginning of the next end step, for each permanent dealt damage this way, its owner puts it on the bottom of their library, then reveals cards from the top until they reveal a nonland permanent card. They put that card onto the battlefield, then shuffle.

Nonstoried creatures lose all abilities and have base power and toughness 1/1. (Enchantments and legendary permanents are storied.)

Exile target nonland permanent. For each of its colors, its controller creates a 1/1 colorless Spirit creature token.

When Ema, the Traveler enters, reveal the top five cards of your library. Put any number of legendary cards revealed this way into your hand and the rest on the bottom of your library in any order.
{2}{B}: Another target legendary permanent gains indestructible until end of turn.

Target nonland permanent phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)
Draw a card.

Enchant nonland permanent
Enchanted permanent's activated abilities can't be activated and triggered abilities of enchanted permanent don't trigger.

Each player sacrifices a creature. If a player lost 3 or more life this turn, each opponent sacrifices a creature instead.

Each player sacrifices a creature and discards a card.
Fuse (You may cast one or both halves of this card from your hand.)

Each player puts the bottom five cards of their library into their graveyard.
Fuse (You may cast one or both halves of this card from your hand.)