msem-instigator

Wild Pyromancy deals 2 damage to each creature, player, and planeswalker. If you cast this spell during your main phase, Wild Pyromancy deals 3 damage to each creature, player, and planeswalker instead.

When Wilderness Forager enters, you may reappropriate. If you do, gain 6 life. Otherwise, gain 3 life. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)

Creatures with power less than or equal to the number of creatures in Wildershrine Elder's pack can't block it. (Two or more creatures you control with equal power are in a pack.)

At the beginning of each player's upkeep, you may exile target permanent that player controls. If you do, return that card to the battlefield under its owner's control at the beginning of the next end step.

When Wilting Waif dies, each opponent discards a card at random and you scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

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.

All creatures get -1/-1 until end of turn.
If ten or more cards are in your graveyard, creatures your opponents control get an additional -1/-1 until end of turn.

Whenever equipped creature deals combat damage to a player, create a 1/1 colorless Thopter artifact creature token with flying.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Flash
Enchant creature
Enchanted creature gets +2/+2 and has flying and “At the beginning of your upkeep, you lose 1 life and create a 1/1 black Harpy creature token with flying.”

Armed — Winterborn Savage gets +1/+1 and has vigilance as long as it's equipped.

Cast a copy of target creature or Revelation card in your graveyard without paying its mana cost. If a Revelation is cast this way, it enters as a Horror creature after it resolves.
Exile Wish to See.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
You may have Witch of Shifting Waters enter as a copy of any creature on the battlefield, except it's an enchantment in addition to its other types.

Whenever Witchfinder Artur enters or attacks, each opponent mills two cards and loses 2 life.
Whenever you cast an instant or sorcery spell, you may exile target instant or sorcery card with mana value less than that spell's mana value from an opponent's graveyard. If you do, cast a copy of the exiled card without paying its mana cost.

Witchseeker Mob's power and toughness are each equal to twice the number of Citizens and/or Peasants you control.
When Witchseeker Mob enters, exile target nonland permanent an opponent controls with mana value less than or equal to Witchseeker Mob's power until Witchseeker Mob leaves the battlefield.

Trample
Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)

When Woken Wave dies, you may exile it. If you do, return target card from your graveyard to the battlefield face down.

When Wondering Oaf dies, return target instant or sorcery card from your graveyard to your hand.

Trample
{5}{G}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

When Woopip Bruiser enters, germinate. When you do, you may have target non-Fungus creature get -X/-X until end of turn, where X is the greatest power among creatures you control. (To germinate, put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

When Woopip Elder enters, germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Destroy target creature or planeswalker, then exile its controller's graveyard.

Double strike
The first spell you cast during each of your turns costs {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.

Vanishing 4 (This permanent enters with four time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a time counter is removed from Worship in Vain, discard your hand, then draw a card for each time counter on Worship in Vain.

When Worship of the Sun enters, draw a card, then choose a card name.
At the beginning of your upkeep, you may tap three untapped creatures you control. If you do, search your library for an enchantment card with the chosen name, put it onto the battlefield, then shuffle.