msem-instigator

Menace
Whenever Auros, Flame-Cursed attacks, it deals 3 damage to each opponent.

When Forbidden Shiangshi Arts enters, each player mills three cards.
{2}{B}: Exile target creature card from a graveyard. Create a tapped token that's a copy of that card, except it has “When this creature deals damage, sacrifice it.”

Whenever Grin, Scourge of Goresand attacks, when you next cast an instant or sorcery spell with mana value 3 or less this turn, copy that spell. You may choose new targets for the copy.
Dash {2}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Artifact vision (Whenever this or another artifact you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Mechanomind Researcher envisions an artifact card, put a +1/+1 counter on it.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
You may cast the first spell that's an enchantment, instant, or sorcery with mana value 1 you cast each turn without paying its mana cost.

Flying
Whenever Phantasmal Owl attacks, it gets +1/+1 until end of turn for each other creature you control with flying.

Whenever Reclamation Grovesculptor enters or attacks, put a growth counter on target noncreature permanent. It becomes a colorless Forest land and loses all other card types and land types.

At the beginning of your upkeep, Suitor of the Sea deals 1 damage to each player.

The Flames Approach deals 3 damage to any target.
Memento {3}{R}{R} (You may cast this from your graveyard for {3}{R}{R}. If you do, put it onto the battlefield transformed after it resolves. Exile it if it would leave the battlefield or not resolve.)