msem-instigator

Lifelink
Augmented — Whenever you cast a spell, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, put a +1/+1 counter on United Guardian. It loses this ability and gains “Whenever United Guardian attacks, create two 1/1 blue Elemental creature tokens with flying that are tapped and attacking.”

Flying
Whenever you cast a spell from your graveyard, return Unliving Swarm from your graveyard to your hand.

When Unmasker of Fate's Design enters the battlefield, 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.

Unreflected Cultist can't be blocked by Reflections.

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.)

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

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Unstable Borer attacks each combat if able.

Menace
Unveil {3}{B}{R} ({3}{B}{R}: Transform this. Unveil only as a sorcery.)

Flash
Deathtouch

Whenever you cast a nongreen spell, creatures you control get +1/+1 until end of turn.
Wanderlust — When Untethered Disciple enters the battlefield, if you control four or more differently named lands, create two 1/1 Scout creature tokens that are all colors.

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.

Assault {1}{R} (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.)
When Urudi Warlord assaults, it gains first strike until end of turn.

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

When Vagabones enters the battlefield, look at the top two cards of your library. Put any number of them into your graveyard and the rest on top of your library in any order.

Valdez's Strike Leader can't be blocked if you have more cards in hand than defending player.

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

Flying
When Valiant Instructor enters the battlefield, you return up to one target enchantment card from your graveyard to your hand.

Advance {3}{R}{W}{B} (Cast this for {3}{R}{W}{B} to advance it as it enters. {3}{R}{W}{B}: Advance this as a sorcery.)
Whenever Valinov Vandal advances, target opponent sacrifices a permanent. Put a +1/+1 counter on Valinov Vandal.

Motivate 1 (When this creature enters the battlefield, 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.

Lifelink
Whenever a creature enters the battlefield from a graveyard, gain control of that creature.

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

Trample
When Varagan Packmaster enters the battlefield, create a Treasure token, then exile the top card of your library. Until the end of your next turn, you may play that card.

When Varakna Wurm enters the battlefield, it deals X damage to target creature an opponent controls, where X is the total number of creature cards you own in exile and in your graveyard.
Cycling {2} ({2}, Discard this card: Draw a card.)