msem-instigator

Enchant creature
When Queenscoming Feast enters, draw a card.
Whenever enchanted creature attacks, create a 1/1 white Peasant creature token.

Flying
At the beginning of combat on your turn, choose one —
• Other creatures you control gain flying until end of turn.
• Other creatures you control with flying get +2/+2 until end of turn.

Invocation — When you spend four or more mana to cast a spell or activate an ability during your turn, transform Corrupted Sorcerer.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever Topan Curemaster encourages a creature, you gain 1 life.

Put target nonland permanent on the bottom of its owner's library. You gain life equal to the number of poison counters its owner has.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Concord — Once each turn, when an opponent casts a spell or activates an ability that targets a Merfolk or enchantment you control, you may counter that spell or ability if there are four or more card types among permanents you control.

Flying, trample

Flying, haste
Erratic (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)
When Splitflame Phoenix dies, you may pay {R}. If you do, return it to its owner's hand.

Flying
Whenever Atieh's Disciple attacks, scry 1.

Destroy all creatures.

Enchant creature
Enchanted creature gets +2/+2.
When Seeking Horizons is put into your graveyard from anywhere other than your library, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Flying, lifelink
Liesa has haste as long as it was foreshadowed.
When Liesa dies, each opponent sacrifices a creature and loses 2 life.
Foreshadow {4}{W}{B} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

{T}: Add {C}.
{1}, {T}: Transform Ruined Theater.

Colossal 4—{5}{G} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {5}{G} as a sorcery: Put four +1/+1 counters on it if it has none.)
Trample

When Savage Savant enters, create a 4/4 green Beast creature token.

When Rootbound Awakener enters, create a green Aura enchantment token named Vivification attached to target creature or land. The token has enchant creature or land and “Enchanted permanent is a creature with base power and toughness 5/5 in addition to its other types.”

When Oracle Crab enters, scry 2. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

When Etched Longspear enters, attach it to target creature you control.
Equipped creature gets +2/+0.
Equip {3}

When Impervious Fortifications enters, you gain life equal to the number of creatures you control.
Creatures can't attack you or a planeswalker you control unless their controller pays {2} for each creature they control that's attacking you.

Sacrifice two other creatures: Monstrosity 2. (If this creature isn't monstrous, put two +1/+1 counters on it and it becomes monstrous.)
When Flailing Terror becomes monstrous, target opponent sacrifices two creatures.

Whenever you cast a red spell, target creature gets +1/+0 and gains haste until end of turn.

Dominance — If you control the creature with the greatest power or tied for the greatest power, you may pay {U} rather than pay this spell's mana cost.
Counter target spell unless its controller pays {3}.

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Whenever you cast a spell, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Gilded Duo gets +2/+0 until end of turn.

{T}: Add {C}.
{T}, Exile two cards from your graveyard: Add {B} or {R}.