msem-instigator

As an additional cost to cast this spell, sacrifice a creature.
Look at the top three cards of your library. Put two of them into your hand and the other into your graveyard.

Mill three cards. When you do, return another nonland card from your graveyard to your hand.

When Whisperwoods Reclaimer enters, if there are three or more land cards in your graveyard, return target land card from your graveyard to the battlefield tapped.

Prowess, haste
Mirage {R} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

When Whiterun Ordainer enters, you gain 4 life.

Escalate {B} (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Wicked Blow deals 3 damage to target player or planeswalker.
• Wicked Blow deals 3 damage to target creature.
• You gain 3 life.

{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.

Flying
Widow Wisp can't block unless you control another Spirit.
When Widow Wisp enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

As an additional cost to cast this spell, you may tap two untapped creatures you control.
Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle. If you tapped two creatures as you cast this spell, create a token that's a copy of that creature, except the token isn't legendary if the creature is legendary.

When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
Inscribe {2}{R}{R} ({2}{R}{R}: 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 you cast a creature spell, if it has a creature type no creature you control has, upgrade Wild Outlander. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Vigilance
• Trample

As long as you control another creature with flying, Wild Skycub has flying.

Colossal 4—{5}{G} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {5}{G} as a sorcery: Put four +1/+1 counters on it if it has none.)
Trample

{B}, {T}: Destroy target tapped creature.

{1}, Sacrifice another creature: Wildborn Swindler deals 1 damage to target player or planeswalker. Scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)
{1}, Discard a card at random: Wildborn Swindler deals 1 damage to you. Draw a card.

At the beginning of combat on your turn, if you control a creature with power 4 or greater, put a +1/+1 counter on Wilderkin Zealot.
{R}{G}: Target creature gains trample until end of turn.

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.

{2}{R/G}: Wildershrine Warden gets +2/+2 until end of turn. You may have it assign its combat damage this turn as though it weren't blocked. Activate only once each turn.

Trample
As long as you control an Elemental creature, Wildheart Gorran gets +1/+1.

Flying
{0}: Willowing Wisp becomes the color of your choice until end of turn.

Destroy target artifact or enchantment.
Cycling {2} ({2}, Discard this card: Draw a card.)

{1}{G}, Remove a -1/-1 counter from a creature you control: Wiltthorn Elemental gets +2/+2 until end of turn.

Deathtouch

Whenever you cast a Knight spell or an Adventure spell, Wimbledon's Squire gets +1/+1 until end of turn.

Create a 1/1 green and white Mouse Soldier creature token with vigilance and a 1/1 white and black Badger Cleric creature token with lifelink.