msem-instigator

Whenever you cast a spell, Wandering Precursor gets +1/+0 until end of turn for each color of mana spent to cast that spell.

Haste
Glorious end — When Warband Lieutenant dies, if it was tapped, put a +1/+1 counter on another target creature you control.

When Ward-Lost Hermit enters, mill three cards.
{2}, {T}, Sacrifice Ward-Lost Hermit: Return target instant or sorcery card from your graveyard to your hand.

Flying
Whenever Warden of the Divine Court attacks, creatures in its pack get +1/+1 until end of turn. (Two or more creatures you control with equal power are in a pack.)

Flying, lifelink

Warped Recluse can't be blocked by creatures with greater power.
Whenever Warped Recluse attacks and isn't blocked, exile target creature defending player controls. At the beginning of that card's owner's next upkeep, return it to the battlefield under their control.

Whenever a creature you control enters for the second time each turn, you may put a +1/+1 counter on Warren Wardens.

Whenever Warrior of Far-Off Sands attacks, it gets +1/+1 until end of turn for each creature you control that's enchanted or equipped.

Wary Rider has first strike as long as its attacking.
Wary Rider gets +1/+0 as long as you control two or more other creatures.

Flying
{1}{W}, {T}: Tap target creature.

Vigilance
Whenever you cast a noncreature spell, you gain 2 life.

Whenever Wavering Sorcerer attacks, you may switch its power and toughness until end of turn.
Unveil {3}{U}{R} ({3}{U}{R}: Transform this. Unveil only as a sorcery.)

Flying, lifelink
At the beginning of each end step, if you gained 3 or more life this turn, choose one —
• Put a +1/+1 counter on Waxing Angel.
• Exile target artifact or enchantment.

At the beginning of your upkeep, each player draws a card.

Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

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

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Weedy Whackers attacks, create a 1/1 green Insect creature token that's tapped and attacking.

Lifelink
Whenever you gain life, each opponent loses 1 life.

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.

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.)

When Whisper Collector dies, draw a card.

Whenever Whisperer of Fortunes attacks, the next card you foretell this turn costs {0} to foretell.
Whenever you cast a foretold spell, put a +1/+1 counter on Whisperer of Fortunes. It gains flying until end of turn.

When Whiterun Ordainer enters, you gain 4 life.