msem-instigator

Stormcharged Pyre enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

When Wealthy Merchants enters, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Whenever Arisen Rider attacks, creatures your opponents control get -1/-1 until end of turn.
If Arisen Rider or another creature or planeswalker would die, exile it instead.

Whenever Wild Dogs of the Night or another Horror you control enters, exile up to one target card in a graveyard. If that card was a creature card, you gain 2 life and put two +1/+1 counters on that Horror.

Reach (This creature can block creatures with flying.)
Whenever Lifespinner Spider blocks or becomes blocked by a creature with flying, you gain 1 life.

Flying
When Lustrous Devout enters, choose one —
• Put a +1/+1 counter on Lustrous Devout.
• Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Whenever a land you control enters or a land card is put into your graveyard from anywhere, create a 0/1 green Plant creature token.
{3}{G}{G}: Put a +1/+1 counter on each other creature you control.

Prevent all damage that would be dealt to each of up to three target permanents this turn.

Careless Violence deals 2 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

When Verendas Spiritwalker enters, you may put a +1/+1 counter on target creature.

The next time target creature would be dealt damage this turn, prevent all but 1 of that damage. Whenever that creature perseveres this turn, put a +1/+1 counter on it. (A creature perseveres when it survives damage.)

Deathtouch
When Jade Empire Outlaw enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

As an additional cost to cast this spell, sacrifice a creature or pay {3}.
Destroy target creature with power 3 or less.

As Alratha, Pearl of the Sand Sea enters, you may have an opponent investigate. If you don't, it enters tapped.
{T}: Add {U}.
{1}{U}, {T}: Investigate.

Choose one —
• Kilnfire deals 1 damage to each creature and planeswalker target player controls.
• Destroy target artifact.

Vigilance
When Worn Peacekeeper dies, create a 1/1 white Soldier creature token with vigilance.

At the beginning of your upkeep, if there are three or more colors among creatures you control, you gain 2 life and draw a card.

Empress Kogane can't attack or block.
Whenever an opponent casts a spell, you may gain life equal to that spell's mana value.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, target creature can't block this turn.

({T}: Add {B} or {R}.)
Ruined Shrine enters tapped unless you control two or more basic lands.

Whenever Wadepool Frog attacks, it gains flying until end of turn.

Create an X/X green and blue Plant creature token, where X is the number of differently named lands you control.

Trample
Qiyan enters with twice X +1/+1 counters on them.
If damage would be dealt to Qiyan while they have a +1/+1 counter on them, prevent that damage, remove that many +1/+1 counters from Qiyan, then create a 0/0 green Hydra creature token and put twice that many +1/+1 counters on it.

Fury Swipes deals 2 damage divided as you choose among one or two targets. Scry 2.

Eager Observer gets +1/+1 as long as you control an artifact or enchantment.