msem-instigator

Whenever one or more creatures attack you or a planeswalker you control, reveal the top card of your library, then put a -1/-1 counter on each attacking creature with the same mana value as the revealed card.

{T}: Add {G}. Spend this mana only to cast a creature spell or activate an ability of a creature.
At the beginning of combat on your turn, if you control a creature with power 4 or greater, Vassal of the Wild gets +2/+1 and gains vigilance until end of turn.

{T}, Pay 1 life: Add {W}.
{T}, Pay 1 life, Sacrifice Vast Savannah: Search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Hexproof
As long as an opponent controls a permanent you own, Vault Sentinel gets +4/+4.

Whenever another artifact is put into your graveyard from the battlefield, each opponent loses 1 life and you gain 1 life.

Ve'aja, the First Bloodline's power is equal to the number of Clerics you control.
Whenever another nontoken creature you control dies, you lose X life and create X 1/1 black Cleric creature tokens, where X is that creature's power.

Flash
Embellish {5}{U} (If you cast this spell for {5}{U}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)
Whenever Vectis Entrancer or another artifact you control enters, tap target creature an opponent controls. It loses all abilities until end of turn.

When Vedalken Machinist enters, create a 1/1 colorless Thopter artifact creature token with flying.
At the beginning of your upkeep, if you control three or more artifacts, draw a card.

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
When Vedalken Reshaper enters, return target instant or sorcery card from your graveyard to your hand.

When Vedalken Wingcrafter enters, create a 1/1 colorless Thopter artifact creature token with flying.

Whenever Vedlinn Ross becomes tapped, exile a nonland card from target opponent's graveyard. Copy it. You may cast the copy this turn. (You still pay its costs, including color. Copies of permanents enter as tokens.)
Whenever you cast a spell from anywhere other than your hand, copy it. You may choose new targets for the copies.

Once each turn, when Vedu, the Deepdrinker enters or you attack with one or more Horrors, you may tap up to two target permanents. If Vedu isn't a token, put two stun counters on each of those permanents.
{2}{U}{U}, Discard Vedu: Create a token that's a copy of Vedu, the Deepdrinker, except it's 4/4 and isn't legendary. Activate only as a sorcery.

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
If casting a noncreature spell would cause an ability of a permanent you control to trigger, that ability triggers an additional time.

Enchant creature
Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
Enchanted creature gets +3/+0 and has menace.

As long as you control exactly one creature, no more than one creature can attack or block each combat.

{B}: Veilborn Hunter gets +1/+1 until end of turn.
Sacrifice another creature: Veilborn Hunter gains indestructible until end of turn. Tap it.

Flash
When Veilborn Meddler enters, counter target spell if its mana value is less than or equal to Veilborn Meddler's power.
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Veilborn Meddler.

Menace
Whenever another creature dies, put a +1/+1 counter on Veilborn Stalker.

{1}{B}, Sacrifice a creature or enchantment: Draw a card.
{4}{B}{B}, {T}: Return target creature or enchantment card from your graveyard to the battlefield with a veil counter on it. That permanent gains “If this permanent would leave the battlefield, exile it instead.”

Whenever Veiled Charmer attacks, target creature blocks it this turn if able.

Veiled Merfolk can't be blocked by creatures with greater power.
When Veiled Merfolk enters, mill a card.

Flying
Concord — At the beginning of your upkeep, if there are four or more card types among permanents you control, exile the top card of your library. You may cast that card this turn without paying its mana cost.

{T}: Add {C}. Spend this mana only to cast an instant or sorcery spell or activate an ability.
{2}{U}: Move a counter from target creature onto another target creature.

Menace, lifelink
Once during each of your turns, if you would gain life, you may create a tapped Treasure token instead.