msem-instigator

At the beginning of your upkeep, if you control three or more creatures, you draw a card and you lose 1 life.
{2}{B}{G}: Create a tapped 1/1 Horror creature token that's all colors.

Glitch {3}{W} (Remove one [restriction] for each time you pay the glitch cost.)
Exile target nonland permanent. [Return it to the battlefield under its owner's control at the beginning of the next end step.]

This spell costs {2} less to cast for each Curse you control.
Flying, vigilance, haste

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
When Soul Trapper enters, tap target creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Soul Trapper.

Bwema, the Ruthless enters with your choice of two different counters on it from among menace, first strike, vigilance, and lifelink.

(As you complete a condition, decode it. After all are decoded, you solve the mystery and transform it.)
When Mystery of the Dying Herds enters, create a 0/2 white Ox creature token.
A creature you control dies.
You have 4 or more life than your starting life total.

Creatures you control get +2/+1 until end of turn.

When Delusive Shadows enters, each opponent loses life equal to the number of cards that player owns in exile.

Draw two cards.

When Citywide Automation enters, create two 1/1 colorless Construct artifact creature tokens.
{2}{W}{W}, Sacrifice Citywide Automation: Creatures you control get +1/+1 until end of turn. Activate only as a sorcery.

As an additional cost to cast this spell, sacrifice a creature.
Look at the top three cards of your library. Put two of them into your hand and the other into your graveyard.

Whenever a permanent you control leaves the battlefield, Second-Day Slayings deals 1 damage to each opponent.

Flying
Wailing Soul has hexproof as long as it's not attacking or blocking.

Trample, haste
When Red Pelt Hart deals combat damage to a player, return it to its owner's hand.
At the beginning of your end step, sacrifice Red Pelt Hart.

Flash
When Hidden Sprout enters, put a +1/+1 counter on target creature.

Kanvar can't attack or block.
Whenever a creature you control with power 4 or greater dies, draw a card.
{R}{G}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words “when,” “whenever,” or “at.”)

This spell costs {X} less to cast, where X is the number of card types among cards in your graveyard.
Flying, ward {2}

When Golna, the First Shah enters, create Shir, a legendary 3/3 white Cat creature token with trample.
Monument {5}{G}{G} (You may cast this transformed from your graveyard for its monument cost. Exile it if it would leave the battlefield or not resolve.)

Whenever a creature attacks you or a planeswalker you control, that creature's controller mills two cards.

{2}: Avaricious Ghul gets +1/+1 until end of turn. If mana from a Treasure was spent to activate this ability, put a +1/+1 counter on Avaricious Ghul instead.

Vigilance
{1}{W}: Barbarian Axe Flinger gains double strike until end of turn.

Bleed {1}{U}{U} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
Look at the top seven cards of your library. Put two of those cards into your hand and the rest on the bottom of your library in any order.

Put two -1/-1 counters on target creature.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Target creature you control becomes a copy of another target creature you control until end of turn.
Showcase {2}{U}{U} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, reveal the top four cards of your library. You may put a creature or land card from among them into your hand. Put the rest on the bottom of your library in a random order.