msem-instigator

Menace
Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)

Create two 1/1 blue Bird creature tokens with flying and “When this creature dies, draw a card.”

Creatures you control dying cause abilities of that creature to trigger as though that creature entered the battlefield.
{2}{W}{B}, Sacrifice another creature: Destroy target nonland permanent.

Each player chooses up to one permanent they control of each permanent type, then sacrifices the rest. (The permanent types are artifact, creature, enchantment, land, and planeswalker.)

Tzelin of the Demon Realm can't block.
Whenever a Demon enters the battlefield under your control, you may pay {B}. If you do, return Tzelin from your graveyard to the battlefield with a +1/+1 counter on it.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Whenever a Demon enters the battlefield under your control, put a +1/+1 counter on Tzelin.
{2}{B}: Sacrifice Tzelin. If you do, each opponent loses life equal to Tzelin's power. If you're in a renaissance, also draw that many cards.

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.)

Other Hounds you control have trample.
{R/W}, {T}: Put a +1/+1 counter on target Hound you control.

{2/B}: Umbral Stalker gains indestructible until end of turn. Tap it.

Resolute — Umbral Wolf can't be blocked by more than one creature as long as Umbral Wolf's power is greater than its base power.

Up to two target creatures each get -3/-0 until end of turn. Tap those creatures. They don't untap during their controller's next untap step.

Whenever Unbudging Badger attacks, if its power is 4 or greater, it gains trample until end of turn.

Target opponent sacrifices half the permanents they control, rounded down.

When Undead Archivist enters the battlefield, return target instant or sorcery card from your graveyard to your hand.
Revive {5}{U} ({5}{U}, 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.)

When Undead Banneret enters the battlefield, if you control a legendary creature, each opponent loses 4 life.

Creature cards in your graveyard have revive {2}{B}{B}. ({2}{B}{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.)

Enchant creature you control
Enchanted creature gets +1/+1.
When enchanted creature dies, return it to the battlefield under your control, then arm it. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Flying
When Unfettered Atrocity enters the battlefield, destroy target creature or planeswalker.

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Creatures you control have base power 4 and gain trample until end of turn.

{G/W}: If Unlikeliest Heroes doesn't have a +1/+1 counter on it, put a +1/+1 counter on it.
{2}{G/W}{G/W}: If Unlikeliest Heroes has a +1/+1 counter on it and doesn't have vigilance, put two +1/+1 counters and a vigilance counter on it.
{3}{G/W}{G/W}{G/W}: If Unlikeliest Heroes has vigilance and not indestructible, put four +1/+1 counters and an indestructible counter on it.

Trample
Whenever Unruly Cannoneer crews a Vehicle, that Vehicle gets +1/+1 and gains trample until end of turn.

Target attacking creature fights another target attacking creature.

Target creature gets -9/-0 until end of turn. 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.”)

Distribute two +1/+1 counters among one or two target creatures.