msem-instigator

Defender
When Wall of Ivy enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Search your library for a Forest or Academy card, put it onto the battlefield tapped, then shuffle.

Ferocious — At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.

Flash
Whenever a permanent with an Adventure you control enters, put a +1/+1 counter on Wandering Dingo.

Wandering Megaflora has hexproof as long as it's untapped.
Whenever Wandering Megaflora attacks, untap another target creature you control.

Assault {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.)
Whenever a creature you control assaults, it gains indestructible until end of turn.

Vanishing 1 (This creature enters with a time counter on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Waning Behemoth enters, you may pay {X}. If you do, put X time counters on it.

Whenever War Priest of Bahet deals combat damage to a player, purge. (Exile two cards that share a type from graveyards. If you do, draw a card.)

War-Pride Champion can't be blocked by creatures with power 2 or less.
Stampede — Whenever War-Pride Champion and a creature with greater power attack, target creature you control gets +2/+2 until end of turn.

Motivate 3 (When this creature enters, you may motivate target creature with lesser power than this by putting three +1/+1 counters on it.)
At the beginning of combat on your turn, you may have target creature you control gain vigilance until end of turn.

Whenever you cast an Elf spell, create a 1/1 green Elf Druid creature token.
Tap four untapped Druids you control: Destroy target artifact or enchantment.

Warden of the Fronds' power and toughness are each equal to the number of Forests you control.
Warden of the Fronds has indestructible as long as you control five or more lands.

Vigilance
Whenever Warfield Excavator attacks, you may exile target card from a graveyard.
Warfield Excavator gets +1/+1 for each card type among cards exiled with it.

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.

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.

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

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.

When Wayfaring Realmstitcher enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Target creature gets +2/+2 until end of turn.
Wanderlust — If you control four or more differently named lands, that creature gets +4/+4 until end of turn instead.

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.)

As Wayward Wanderers enters, you may have it become X/X with ward {X} and “Other creatures you control have base power and toughness X/X.”
{1}{G}: Return Wayward Wanderers to its owner's hand.

When Weald Sentry enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
When Weald Sentry dies, draw a card.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
When Weathered Veteran dies, you may put a -1/-1 counter on target creature.

Reach
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.)