msem-instigator

Each opponent sacrifices a creature. For each creature sacrificed this way, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

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

Whenever Wild Bearmaster attacks, each other attacking creature you control gets +X/+X until end of turn, where X is Wild Bearmaster's power.

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 it dies, each opponent draws a card” as long as it has a bounty counter on it.)

Whenever Wild Dogs of the Night or another Horror enters the battlefield under your control, exile up to one target card in a graveyard. If that card was a creature card, you gain 2 life and put two +1/+1 counters on that Horror.

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.

When Wild Entourage enters the battlefield, create two 1/1 colorless Construct Actor creature tokens.
{4}{G}: Wild Entourage gets +2/+2 and gains trample until end of turn.

Target creature gets +2/+2 and gains trample until end of turn.

When Wild Festivities enters the battlefield or at the beginning of your upkeep, you may put a creature card from your hand onto the battlefield. If you do, each opponent creates a 1/1 blue Frog creature token.

Gain control of target land.

Erratic (When this creature dies, reveal the top four cards of your library. Put a creature card that costs less than this revealed this way onto the battlefield and the rest on the bottom of your library in any order.)
When Wild Gravetender enters the battlefield, you gain 2 life for each creature card in your graveyard.
{1}{G}, Sacrifice a creature: Return Wild Gravetender from your graveyard to your hand.

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.)

Target creature you control gets +2/+2 until end of turn. It fights target creature an opponent controls.

Riot (This creature enters the battlefield with your choice of a +1/+1 counter or haste.)
Whenever Wild Lifescale attacks, proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

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.

Create three 1/1 red Goblin creature tokens.

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

Whenever a creature blocks Wildborn Courtesan, draw a card.
{R}{R}: Untap target creature an opponent controls. That creature blocks Wildborn Courtesan this turn if able.

Assault {2}{G} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Wildborn Marauder assaults, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

When Wildborn Merchant enters the battlefield, each player discards their hand, then draws X cards, where X is the number of Nobles you control.

When Wilderness Forager enters the battlefield, 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.)

Wildfire Elemental has frenzy 4 as long as you control no other creatures. (Whenever this creature attacks and isn't blocked, it gets +4/+0 until end of turn.)
Wildfire Elemental has frenzy 4 as long as you have no cards in hand.

Harmony — You may pay {1}{G}. If you do, create a 3/3 green Beast creature token.
When Wildheart Chorister enters the battlefield, harmonize. (Trigger up to one harmony of a permanent you control.)