msem-instigator

When Chamber of Penance enters, exile target nonland permanent an opponent controls until Chamber of Penance leaves the battlefield.

Discard your hand, then draw two cards for each land card discarded this way. For each opponent, Marzen's Frenzy deals damage to that player or a planeswalker they control equal to twice the number of instant or sorcery cards discarded this way.

Tap up to two target creatures. Germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Destroy up to one target artifact.
Amass Soldiers 2. (Put two +1/+1 counters on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)

{1}, {T}: Draw a card, then exile a card from your hand face down until Cluttered Study leaves the battlefield. (It returns to your hand.)
{3}, {T}: Shuffle Cluttered Study into its owner's library.

Enchant creature
As Legacy of Siltbottom enters, choose a creature type.
Enchanted creature gets +3/+3 and is the chosen type in addition to its other types.

Resolute — {T}: Grizzled Cutthroat deals 1 damage to any target. Activate only if Grizzled Cutthroat's power is greater than its base power.

Menace
Stampede — Whenever Maelstrom Slicer and a creature with greater power attack, exile the top three cards of your library. You may play those cards until end of turn.

Menace
Whenever Hui Zhou, the Dark Visage perseveres, you may destroy another target legendary creature. (A creature perseveres when it survives damage.)

When Third Legion Rider enters, if you control an embattled creature, tap target creature an opponent controls. It doesn't untap during its controller's next untap step. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Your life total becomes 0. Until an opponent's next turn, you can't lose the game, your opponents can't win the game, and you can't gain life.
Take an extra turn after this one.
Exile Buy Time.

Create a 1/1 white Soldier creature token with vigilance.
At the beginning of combat on your turn, you may pay {2}{W}. If you do, creatures you control get +1/+1 until end of turn.

You may cast this spell without paying its mana cost if it targets a spell you control.
You may choose new targets for target spell.

Indestructible
When Dark Behemoth dies, return another target creature card from your graveyard to the battlefield.

{1}, {T}: Exile target creature you control until Elsewhere Mirror leaves the battlefield. (It returns to the battlefield under its owner's control.)
{3}: Choose a permanent card exiled with Elsewhere Mirror. Target creature becomes a copy of that card until end of turn.

When Percy's Perfect World enters, search your library for a legendary white card, reveal it, put it into your hand, then shuffle.
If an effect would create one or more creature tokens under your control, it creates twice that many of those tokens instead.

If an opponent controls more lands than you, search your library for a Plains card. If an opponent controls more creatures than you, search your library for a creature card with mana value 2 or less. Reveal those cards, put them into your hand, then shuffle.

Create two Idol tokens, then counter target spell unless its controller pays {1} for each Idol you control. (They're artifacts with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Dismal Backwater enters tapped.
When Dismal Backwater enters, you gain 1 life.
{T}: Add {U} or {B}.

Hanweir Miscreant can't be blocked by creature tokens.
{2}{R}: Transform Hanweir Miscreant. Activate only if it's attacking.

Put a +1/+1 counter on target creature.
Flashback {1}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Whenever a creature dies, create a 1/1 red and green Warrior creature token if this is the first time this ability has resolved this turn. Otherwise, you draw a card and you lose 1 life.

When Gulch Glutton enters, create a 1/1 black Rat creature token.
Whenever Gulch Glutton perseveres, each player sacrifices a creature. (A creature perseveres when it survives damage.)

You may pay {B} and 4 life rather than pay this spell's mana cost.
Target creature gets -5/-5 until end of turn.