msem-instigator

When Gharsha, Monstrous Quarry enters, each opponent creates a 1/1 green Elf creature token.
Whenever a creature you control becomes blocked, you may pay {1}. If you do, put a +1/+1 counter on that creature.

Whenever one or more creatures you control deal combat damage to a player, exile a nonland card from that player's graveyard. Copy it. You may cast the copy. (You still pay its costs, including color. Copies of permanents enter as tokens.)

{4}{R}, Sacrifice Lavahurler: It deals 5 damage to target player or planeswalker.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

{T}: Scry 1.
{1}{U}, {T}: Reveal the bottom card of your library. If it's an artifact or enchantment card, put it into your hand.

Reprise {2}{W} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)
You gain 2 life. Then distribute X +1/+1 counters among creatures you control, where X is the amount of life this spell caused you to gain.

As an additional cost to cast this spell, discard a card.
Return target card from your graveyard to your hand.

You may pay {W}{U}{B}{R}{G} rather than pay this spell's cost.
When Suncolored Dreamer enters, draw a card.

Advanced Powercell enters tapped.
{T}: Add one mana of any color.

Target creature you control and each other creature in its pack deal damage equal to their power to target creature or planeswalker. (Two or more creatures you control with equal power are in a pack.)

Destroy target creature that isn't in a pack. (Two or more creatures a player controls with equal power are in a pack.)

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] You may discard a card. If you do, draw a card.
[Lore III] Create a token that's a copy of another target creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Enchant creature
When Paid in Blood enters, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Enchanted creature gets +1/+1 and has lifelink.

{T}: For each color among enchantments you control, add one mana of that color.
{2}{G}{G}, Sacrifice Sower of Seeds: Shuffle any number of enchantment cards from your graveyard into your library. Create an X/X black Horror creature token, where X is the number of enchantment cards shuffled into your library this way.

As long as an opponent has one or fewer cards in hand, Valdez gets +2/+0 and has menace.

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

Haste
Whenever a creature dealt combat damage by Cutthroat Carnie this turn dies, you may have Cutthroat Carnie fight target creature.

Civilized — At the beginning of your upkeep, if you control an artifact, a creature, and an enchantment, you draw a card and you lose 1 life.

Create a 2/2 red Dragon creature token with flying and haste.
Whenever a nontoken Dragon you control attacks, you may return Flynn's Wonder from your graveyard to your hand.

Machinate — {T}, Tap another untapped artifact you control: Exile target artifact or creature, then return that card to the battlefield tapped under its owner's control.

Choose any target. Change the text of target instant or sorcery spell to “This spell deals 3 damage to the chosen target. Draw a card.”

When Golden Grizzly enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

When Into the Lion's Den enters, target opponent reveals their hand. You choose a nonland card from it and exile that card until Into the Lion's Den leaves the battlefield.

Flying
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

{B}, Sacrifice a creature: Put a +1/+1 counter on Lightwrencher.