msem-instigator

When a creature you control scavenges Wanderer of Many, create a token that's a copy of that creature. Put a +1/+1 counter on the copy.
Scavenge {3}{U} ({3}{U}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Whenever Wanderer of Oblivion enters or attacks, exile target card from a graveyard.
You may play cards exiled with Wanderer of Oblivion.

Wanderer's Sky enters tapped.
As Wanderer's Sky enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

If Wandering Domovoi would be dealt noncombat damage, prevent that damage and put three +1/+1 counters on Wandering Domovoi instead.

Whenever Wandering Doyen is dealt damage, it deals that much damage to you.
{4}{R}: Attacking creatures you control get +1/+0 and gain first strike until end of turn.

({T}: Add {G} or {W}.)
Wandering Hamlet enters tapped unless you control two or more basic lands.

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.)
Draw a card.

Lifelink, haste
Wanton Cleaver has first strike as long as it's attacking.

{T}: Add {C}.
{5}, {T}, Sacrifice War Golem Forge: Create a 3/3 colorless Golem artifact creature token.

{T}: Add {C}.
{1}, {T}, Sacrifice War-Torn Tundra: Arm target creature you control. Activate only as a sorcery. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

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

Prevent all noncombat damage that would be dealt to equipped creature.
Equipped creature has hexproof as long as it's your turn.
Equip {1}

Enchant creature
Enchanted creature has double strike and “Other creatures you control have first strike.”

Prevent all damage target attacking creature would deal this turn. If there is a card named Warning Shot in your graveyard, exile that creature.

{T}: Add {C}.
{2}, {T}, Sacrifice Warped Landscape: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

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

Target creature you control gets +1/+1 and gains indestructible until end of turn.
Fabled {3}{W}{W} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

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.

Advance {3} (Cast this for {3} to advance it as it enters. {3}: Advance this as a sorcery.)
Whenever Wastes Scrambler advances, put your choice of a +1/+1, first strike, menace, trample, or vigilance counter on it. If {R}{W}{B} was spent to advance it, repeat this process twice.
Crew 1

Target player mills two cards.
Draw a card.
Coalesce {6}{U} (You may cast this from your graveyard for {6}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

{4}{B}{R}: Exile Watch the World Fade from your hand with seven apocalypse counters on it.
At the beginning of your upkeep, if Watch the World Fade is exiled, remove an apocalypse counter from it. If you do, each opponent loses 3 life unless they discard a card or sacrifice a nonland permanent. When you remove the last counter this way, each player loses the game.

Flying
Whenever a nontoken, noncreature, nonland permanent you control enters, create a token that's a copy of that permanent except it has no mana cost and it isn't legendary.

Vigilance, reach
Watchful Authority can block an additional creature each combat.