msem-instigator

Enchant creature
Enchanted creature can't become untapped.
{4}{U}: Return Frozen Halo and enchanted creature to their owners' hands.

This spell costs {4} less to cast if a player attacked with four or more creatures this turn.
End the turn.

Put target creature on the bottom of its owner's library. That player reveals cards from the top of their library until they reveal a creature card, then puts all cards revealed this way into their graveyard.

Choose one —
• Return all tapped creatures to their owners' hands.
• Return all untapped creatures to their owners' hands.

Return target creature to its owner's hand. You may have another target creature gain flying until end of turn.

(Transform this if it's not attached to a creature. Pay {3}{U} as a sorcery to unattach it.)
Enchant creature you control
Gamhaugen Warbeast's rider gets +2/+2 and has flying.

Pressure {1}{U}{U} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Draw three cards.

Enchant opponent
Enchanted player plays with the top card of their library revealed.
Whenever enchanted player casts a spell, you may have them mill a card.

Choose flying, prowess, vigilance, or ward {2}. Create a colorless Equipment artifact token with “Equipped creature has the chosen ability” and equip {2}. (Then exile this card. You may cast the creature later from exile.)

When Geistmage's Grimoire enters, draw two cards.
{4}{U}, {T}: Target creature can't be blocked this turn.

Draw two cards.
You may cast an instant or sorcery spell with mana value 3 or less from your hand or graveyard without paying its mana cost. If that spell would be put into a graveyard, exile it instead.

Target permanent phases out. (Then exile this card. You may cast the artifact later from exile.)

Put a +1/+1 counter on target creature you control. It can't be blocked this turn.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Whenever you cast a spell during an opponent's turn, put a charge counter on Gift of the Sphinx.
At the beginning of your upkeep, draw a card for each charge counter on Gift of the Sphinx.

Create a 2/2 colorless Spirit creature token.
Draw a card.

When Gilded Authority enters, create two Treasure tokens. (They're artifacts with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Creatures your opponents control get -1/-0.

You may pay {U} and tap an untapped Rogue you control rather than pay this spell's mana cost.
Counter target spell unless its controller pays {2}.

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
Untap each Horror you control during enchanted creature's controller's untap step.

Aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)
Draw a card.

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Draw two cards. [Then discard two cards.]

Draw three cards. Discard your hand at the beginning of the next end step.

Return target nonland permanent to its owner's hand. If you control an Elemental, draw a card.

Look at the top two cards of your library. Put one of them into your hand and the other into your graveyard.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

At the beginning of your upkeep, scry 1.
At the beginning of combat on your turn, if you cast both a creature spell and a noncreature spell this turn, you may have Glintwing Nest become a 4/4 Elemental Bird creature with flying in addition to its other types until end of turn.