msem-instigator

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
{3}{U}: Target creature gains slipstream until end of turn.

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.

Flying
Cycling {2} ({2}, Discard this card: Draw a card.)

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

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

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

Whenever Weaver of Lore attacks, you may reveal your hand. Weaver of Lore gets +2/+2 until end of turn if you reveal two or more blue cards this way.

When Weaver of Mists enters, substantiate target card in your graveyard. (Put it onto the battlefield face down as a 2/2 creature. You may turn it face up and cast it at any time for its mana cost if it isn't a creature.)
Spells you cast from anywhere other than your hand cost {1} less to cast.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Weaver of the Winds envisions an instant or sorcery card, draw a card.

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

Flying
Welkin Tern can block only creatures with flying.

Wharf Lumper can't be blocked by creatures with greater power.
Whenever Wharf Lumper attacks, mill a card. If that card was an instant or sorcery, Wharf Lumper gets +3/+0 until end of turn.

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.

Flash
Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)

When Whisper Collector dies, draw a card.

When Whisper Witch enters, choose up to one target creature. That creature's controller mills four cards, then puts that creature on top of their library.