msem-instigator

As Warmonger Contraption enters, choose a creature type.
Warmonger Contraption is the chosen type in addition to its other types.
Warmonger Contraption's power and toughness are each equal to the number of creatures of the chosen type you control.

{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.

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.

Each creature with power greater than its toughness doesn't untap during its controller's untap step.

Equipped creature gets +1/+1.
As long as equipped creature is a Warrior, it has first strike.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Whenever equipped creature attacks or blocks, it gets +3/+3 and gains hexproof until end of turn.
Equip {1}

Enchant creature
When Warrior's Discipline enters, put a +1/+1 counter on enchanted creature.
Whenever enchanted creature deals combat damage to a player, double the number of +1/+1 counters on it.

Creatures you control get +1/+0 and attack each turn if able.
As long as you control four or more Mountains, attacking creatures you control get an additional +1/+0 and have first strike.

You may put a Dragon creature card from your hand onto the battlefield. That creature gains haste until end of turn. Return it to its owner's hand at the beginning of the next end step.

Trample, prowess
You may exert Wartorn Veteran as it attacks. When you do, double its power until end of turn. (An exerted creature won't untap during your next untap step.)

Haste
When Wasteland Rabblerousers enters, creatures your opponents control with power X or less can't block this turn, where X is the number of Deserts you control.

First strike
Wither (This deals damage to creatures in the form of -1/-1 counters.)

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

Trample, haste
Defiance (Whenever this creature takes damage, if it survives and wasn't defiant, put a +1/+1 counter on it and it becomes defiant.)
Whenever Wastewolf attacks, it deals 1 damage to any other target.

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.

Whenever Watchkeeper Deserter attacks, discard up to two cards, then draw that many cards. Watchkeeper Deserter gets +X/+0 until end of turn, where X is the total mana value of the discarded cards.

Remove all -1/-1 counters from target creature. That creature gets +3/+3 and gains trample until end of turn.

Watchkeeper's Retort deals 2 damage to target creature 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.)

As an additional cost to cast this spell, discard a card.
Create three 1/1 red Soldier creature tokens with haste.

Waterfront Market enters tapped unless you control a basic land.
{T}: Add {W} or {U}.

Prowess
Whenever you cast a noncreature spell, target creature can't block this turn.

When Wavebreaker enters, add two mana of any one color. You can't spend this mana to cast spells.

Pressure {3}{G} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Put two +1/+1 counters on target creature you control if Way of the Danithra was cast for its pressure cost. Then it fights up to one target creature you don't control.