msem-instigator

Assault {1}{B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
Whenever a creature you control assaults, you may have target creature get -2/-2 until end of turn.

Dead Man's Hand enters tapped.
{T}, Sacrifice Dead Man's Hand, two permanents with mana value 1, and two permanents with mana value 8: Target player loses the game.

{T}: Add one mana of any color a basic land you control could produce.

You may cast target instant or sorcery card from your graveyard this turn. If that spell would be put into your graveyard, exile it instead.

Menace
When Beatrice enters, target opponent reveals their hand. Exile a nonland card from it. During any turn that player lost life, you may cast that card and mana of any type can be spent to cast that spell.

Whenever Journeying Giftbearer or another nontoken creature you control enters, create a green and white Aura enchantment token named Wild Boon attached to that creature. The token has enchant creature and “Enchanted creature gets +1/+1.”

Haste
Madness {3}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

When Steamwork Musicians enters, creatures you control get +1/+0 until end of turn.

Madness {4}{G}{G} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
Look at the top eight cards of your library. You may reveal a creature card from among them and put it into your hand, then put the rest on the bottom of your library in a random order. Then if this spell was cast for its madness cost, you may put a creature card from your hand onto the battlefield.

This spell costs {2} less to cast if you control a legendary creature.
Search your library for a creature or land card, reveal it, put it into your hand, then shuffle.

Gloomtide Gulf enters tapped.
{T}: Add {U} or {B}.
{1}, {T}: Add one mana of any color.

Target player discards two cards.
Fabled {3}{B}{B} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that player.)

Counter target instant or sorcery spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Put target creature card from a graveyard onto the battlefield under your control. That creature is a black Zombie in addition to its other colors and types.

When Shojiro, the Wavewaker enters, submerge up to eight target creatures your opponents control. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Ward {1}
Other Scouts you control get +1/+1.
Whenever three or more Scouts you control attack, draw a card.

(Add a quest counter as this enters. Sacrifice after 6.)
2, 3, 4, 5 — Whenever you cast an instant or sorcery spell from your hand, add a quest counter.
6 — Exile target instant or sorcery spell you control instead of putting it into your graveyard as it resolves. You may cast that card from exile until Awaken the SOURCE leaves the battlefield.
Exile target instant or sorcery spell you control as it resolves. Until end of turn, you may cast cards exiled with Awaken the SOURCE without paying their mana costs.
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When The Lonely Prophet enters, exile a card you own from outside the game face down.
Whenever The Lonely Prophet deals combat damage, put the exiled card into your hand.

Enchant creature
Enchanted creature gets +2/+2, can't be the target of spells or abilities you don't control unless their controller controls no untapped lands, and can't be blocked unless all creatures defending player controls that are able to block it do so.

Counter target nonenchantment spell.

When Renili, Telenian Weaponist enters, you may exile another target creature until Renili leaves the battlefield.
When Renili leaves the battlefield, put a +1/+1 counter on each creature you control.

When Stygian Leviathan enters, target opponent loses life equal to the number of Curses attached to them and you gain that much life.

Flying
When Dewdrop Ordainer dies, put a +1/+1 counter on target creature you control with a counter on it.

Creature tokens you control have hexproof.
{3}{G}: Put a +1/+1 counter on target creature token.