msem-instigator

Advance {3} (Cast this for {3} to advance it as it enters. {3}: Advance this as a sorcery.)
Whenever Wastes Scrambler advances, put your choice of a +1/+1, first strike, menace, trample, or vigilance counter on it. If {R}{W}{B} was spent to advance it, repeat this process twice.
Crew 1

Whenever Wasting Soul attacks or blocks, sacrifice a creature, then put two +1/+1 counters on Wasting Soul.

Prowess
Whenever you cast a noncreature spell, target creature can't block this turn.

When Wayfaring Realmstitcher enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

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.

If a source would deal damage to a creature this turn, prevent all but 1 of that damage.

When Weedy Wanderer leaves the battlefield or phases out, put a +1/+1 counter on a creature you control.

Advance {5}{B}{B} (Cast this for {5}{B}{B} to advance it as it enters. {5}{B}{B}: Advance this as a sorcery.)
Whenever Well-Oiled Sniper advances, target creature gets -3/-3 until end of turn.

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.)

Creatures can't attack or block alone.

You may play an additional land this turn.
Return target permanent card from your graveyard to your hand. Exile Whispers of the Dark.

{2}, Sacrifice Wicked Fossil: Target player loses 2 life and you gain 2 life.
{2}{B}{B}: Return Wicked Fossil from your graveyard to the battlefield transformed. Activate only during your turn.

Menace
Whenever Wightclaw deals combat damage to a player, that player discards a card and you draw a card.

Target creature gains lifelink or winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)
Put the bottom card of your library into your hand.

Whenever one or more creatures you control attack, you may post a bounty on target creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

You may put a creature or planeswalker card from your hand onto the battlefield. It gains haste. Sacrifice it at the beginning of the next end step. Whenever an ability of that permanent is activated this turn, you may copy that ability. You may choose new targets for the copy.

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Wild Haploc has first strike as long as it's attacking.

When Wild Hermit dies, create a 2/2 white Cat creature token.
Revive—{3}{G}{G}, Sacrifice a creature. ({3}{G}{G}, Sacrifice a creature, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Whenever you cast a noncreature spell, Wild Pyromancer gets +1/+1 until end of turn.
Whenever Wild Pyromancer attacks, you may pay {2}{R}. If you do, transform Wild Pyromancer.

When Wild Waypoint enters, create a 1/1 green Scout creature token.
{T}: Add {B}, {G}, or {U}.