msem-instigator

Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
Return target nonland permanent to its owner's hand. If this spell was harnessed, draw a card.

Advance {2}{W} (Cast this for {2}{W} to advance it as it enters. {2}{W}: Advance this as a sorcery.)
Whenever Construct Engine advances, create a 1/1 colorless Construct artifact creature token.

When Contagious Host dies, each player loses 1 life.
Revive {2}{B} ({2}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

Investigate, then counter target spell unless its controller pays {1} for each Clue you control. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Controlled Burn deals 2 damage to target player or planeswalker.
At the beginning of your upkeep, you may exile Controlled Burn from your graveyard. If you do, it deals 2 damage to target player or planeswalker.

Flash
Whenever you draw a card during an opponent's turn, you get a glory counter. (You lose glory counters before life. A player with ten or more glory counters wins the game.)

Whenever Coral Hunter attacks, another target creature can't be blocked this turn.

Whenever you cast a white spell, creatures you control get +1/+0 until end of turn.
Whenever you cast a blue spell, draw a card, then discard a card.

[+2]: Put two +1/+1 counters or loyalty counters on up to one other target creature or planeswalker.
[0]: Cornrose, the Mighty deals 3 damage to target creature. That creature deals damage equal to its power to Cornrose.
[–2]: Until end of turn, target creature gets +X/+X and gains trample, where X is its power.

({T}: Add {B}.)
Corpsebed enters the battlefield tapped.
When Corpsebed enters the battlefield, exile up to two target cards from graveyards.

Return target creature or planeswalker card from your graveyard to the battlefield. If that card was a creature, it's an Actor in addition to its other types.

Each player reveals the bottom six cards of their library. For each player, put up to one permanent card revealed this way onto the battlefield under your control.

Flying
{1}{B}, {T}: Destroy target creature that was dealt damage this turn.

Whenever you cast a white spell, target player loses 2 life and you gain 2 life.
Whenever you cast a green spell, put a +1/+1 counter on Corrupted Warlord.

Enchant creature
Enchanted creature gets -3/-3 and has “At the beginning of your upkeep, you lose 3 life.”

As Coveted Tower enters the battlefield, you may pay 3 life. If you don't, it enters the battlefield tapped.
{T}: Add {G}, {U}, or {R}.

{1}{R}, Sacrifice Crackling Seaform: Counter target spell unless its controller has Crackling Seaform deal 3 damage to them.

Cradle of Corruption enters the battlefield tapped.
Whenever a creature dies, put a creation counter on Cradle of Corruption.
{T}, Remove ten creation counters from Cradle of Corruption and sacrifice it: Put up to two target creature cards from graveyards onto to battlefield under your control. Activate only as a sorcery.

Crafted Coast enters the battlefield tapped unless another player controls a land that could produce {W} or {U}.
{T}: Add {W} or {U}.

Flying
Cragstalker Eagle gets +2/+2 as long as you've cast a creature spell and a noncreature spell this turn.
You may cast Adventure spells and spells with Adventures from your hand as though they had flash.

Each player reveals their hand. Choose a creature card revealed this way. Its owner discards it.
{2}{B}{B}, Exile Cranial Violation and six other cards from your graveyard: Put target creature card from a graveyard onto the battlefield under your control. Activate only as a sorcery.

Target creature gets +X/+0 and gains trample until end of turn.

{1}{R}: Crashcaller Nereid gets +1/+0 and gains trample until end of turn.