msem-instigator

When Unmasker of Fate's Design enters, look at target player's hand. Choose a nonland card from it and exile that card with a puzzle counter on it. As long as that card has a puzzle counter on it, that player may pay {2} and 1 life at any time. If they do, return the exiled card to their hand.

Trample
Whenever Unruly Cannoneer crews a Vehicle, that Vehicle gets +1/+1 and gains trample until end of turn.

Prowess
Whenever Unseen Hand attacks, exile target noncreature, nonland card with mana value 1 or less from your graveyard. Copy that card. You may cast the copy. (You still pay its costs.)

Discard a card: Unseen Maniac gets +1/+1 and can't be blocked this turn.
Whenever Unseen Maniac deals combat damage to a player, draw a card.

Glitch—Sacrifice a creature. (Remove one [restriction] for each time you pay the glitch cost.)
When Unshackled Revolutionary enters, you may destroy target creature an opponent controls [with mana value 3 or less]. [You lose 3 life.]

Flash
Deathtouch

{T}: Target attacking or blocking creature gets +1/+1 until end of turn.

Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Unwavering Questant can't block.
When an opponent fails a trial, return Unwavering Questant from your graveyard to the battlefield.

When Unwitting Fanatic enters, create a 3/2 colorless Horror creature token.
Sacrifice Unwitting Fanatic: Another target permanent you control gains hexproof and indestructible until end of turn.

Unyielding Aswaran can't be blocked by Armies.

When Urisk Fiddler enters, draw a card.

First strike (This creature deals combat damage before creatures without first strike.)

Whenever V-4 Fixit or another artifact you control enters, target creature you control gets +1/+1 until end of turn.

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
When Vaeldan's Liberator dies, you may exile it. If you do, return a permanent card with mana value less than or equal to Vaeldan's Liberator's power from your graveyard to your hand.

When Vagabond of the Dunes enters, each opponent discards a card.
Whenever an opponent discards a card, put a +1/+1 counter on Vagabond of the Dunes.
Surpass {5}{B} ({5}{B}: Transform this creature. This costs {1} less to activate for each counter
on it. Activate only as a sorcery.)

Valeron Vanguard can't be blocked by 1/1 creatures.

Motivate 1 (When this creature enters, you may motivate target creature with less power than this by putting a +1/+1 counter on it.)
{2}{W}{W}: Exile Valtrian Cavalier, then return it to the battlefield under your control.

Vampire Partaker can't block.
Sacrifice a creature: Put a +1/+1 counter on Vampire Partaker. You gain 1 life. Activate only as a sorcery.

{3}{W}: Exile Vanishing Memory and target creature an opponent controls.

Flying (This creature can't be blocked except by creatures with flying or reach.)
Vaporkin can block only creatures with flying.

{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.

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

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.

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