msem-instigator

Target player mills four cards.
Dominance — That player mills eight cards instead if you control the creature with the greatest power or tied for the greatest power.

Create two Idol tokens, then counter target spell unless its controller pays {1} for each Idol you control. (They're artifacts with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Counter up to one target spell unless its controller pays {2}. Until end of turn, you may cast spells as though they had flash.

Create an 8/8 blue Kraken creature token.
{2}{U}, Discard Wealth of the Flood: Create a Treasure token. Scry 2.

Creatures you control get +0/+2 and gain hexproof until end of turn.

Counter target spell if you have more cards in your graveyard than that spell's controller.

Enchant permanent
Whenever enchanted permanent becomes untapped, its controller gets a poison counter.

Augmented — If you've spent {W}{U}{B}{R}{G} to cast spells this turn, you may cast this spell without paying its mana cost.
Counter target spell.

Draw two cards, then discard two cards. Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Whenever you draw a card, target player mills two cards.
Whenever you cast a blue spell, scry 1, then you may reveal the top card of your library. If it's an instant or sorcery card, draw a card.

Return target nonland permanent to its owner's hand. Scry 1.

Draw two cards, then discard two cards if it's a combat step.
Quickdraw {U} (When a creature you control blocks or becomes blocked, you may cast this spell for {U}.)

Return target creature to its owner's hand. If you controlled that creature, draw a card.

Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
Return each nonland permanent your opponents control to its owner's hand.

Put target instant or sorcery card from your graveyard on top of your library.
Inscribe {3}{U} ({3}{U}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Whenever an opponent casts a spell, that player mills X cards, where X is that spell's mana value.

Surveil 1, then draw a card. (To surveil 1, look at the top card of your library. You may put that card into your graveyard.)
Create a tapped Treasure token.

Enchant creature
You may cast this spell from your graveyard if it targets a legendary creature you control.
Enchanted creature gets +2/+2 and has flying.

Counter target spell that targets you or a permanent you control. If that spell targeted a creature, put a +1/+1 counter on that creature.

Exile the top five cards of your library. An opponent separates them into two piles. You may put one pile into your hand or draw two cards. Then put the rest of the piles into your graveyard.

Attacking creatures get -X/-0 until end of turn.

Gain control of target creature if its power is less than or equal to the number of cards in your hand.
Quickdraw {4}{U}{U} (When a creature you control blocks or becomes blocked, you may cast this spell for {4}{U}{U}.)

Choose any number of permanents and/or players, then give each another counter of each kind already there.
Flashback {2}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Converge — Draw a card for each color of mana spent to cast Wisdom of the Leylines. Then discard a card.

Flash
You may cast spells as though they had flash.