msem-instigator

Flying
Whenever another creature you control enters, you may have Waxing Celestial get +1/+1 until end of turn.

Target creature gets +1/+1 and gains first strike until end of turn. Untap it.

At the beginning of your end step, if you cast no spells this turn, untap target creature.

Whenever you gain life, put a +1/+1 counter on Wayfaring Pilgrim.

When Wayfaring Swindler enters, destroy all permanents attached to target creature.

When Weary Adventurer enters, return a permanent you control to its owner's hand.

{T}, Exert Weary Border Guard: Tap target creature. (An exerted creature won't untap during your next untap step.)

Flash (You may cast this spell any time you could cast an instant.)
Defender
When Weary Steward enters, prevent all combat damage target creature would deal this turn.

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

Whenever you attack or block with one or more other creatures, Wehre-District Patrollers gets +1/+0 and gains first strike until end of turn.

Enchant creature
Enchanted creature gets +2/+2 as long as it's legendary. Otherwise, it can't attack or block.
When enchanted creature dies, if it's legendary, return that card to its owner's hand.

Enchant creature
Enchanted creature has flying.
{2}: Tap enchanted creature.

When Weizenmother enters, return target creature card with mana value 3 or less from your graveyard to the battlefield.
Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Whenever West Ward Purifier becomes tapped, you gain 1 life.

You gain 5 life and draw a card. Then if you've cast spells named When the Stars Align five times this game, you win the game.
Augmented — If you've spent {W}{U}{B}{R}{G} to cast spells this turn, you may shuffle When the Stars Align into your library.

Flash
Whenever Whimsical Dancer enters or is exerted, target creature gets +1/+0 and gains first strike until end of turn.
You may exert Whimsical Dancer as it attacks. (An exerted creature won't untap during your next untap step.)

Flying, lifelink
Creatures entering or leaving the battlefield don't cause abilities to trigger unless that creature is in a pack. (Two or more creatures a player controls with equal power are in a pack.)

Enchant creature
Enchanted creature can't attack or block.
{2}{U}: Return Whiplash and enchanted creature to their owners' hands.

Create a 1/1 white Spirit creature token with flying.
Whenever a nontoken creature you control dies, you may pay {W} and exile Whispered Wishes from your graveyard. If you do, create a 1/1 white Spirit creature token with flying.

Double strike

Vigilance

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)

When Whiterun Ordainer enters, you gain 4 life.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)