msem-instigator

When Vasille Rioters enters, conjure three cards named Vasille Rioters and shuffle them into your library, then you get a riot counter.
Vasille Rioters gets +1/+1 for each riot counter you have.

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.

Counter target spell unless its controller pays {3}.

Choose one—
• Destroy target permanent with mana value 2.
• Return target permanent card from a graveyard to its owner's hand.
Exile Veil's Recovery.

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.

Adorned — At the beginning of your end step, if Venerated Knight is equipped and/or enchanted, put a +1/+1 counter on it.

Haste
Whenever you cast a noncreature spell, put a +1/+1 counter on Vengeant Precursor. It gains trample until end of turn.

Whenever a Survivor you control dies, each opponent loses 1 life and you gain 1 life.

Opponents drawing a card during your turn causes one death knell of a permanent you control to trigger.
Death knell — Spells target opponent casts this turn cost {1} more to cast. (As a creature you control dies, trigger one death knell of that creature or another permanent you control.)

Enchant creature
Enchanted creature gets -X/-X, where X is the number of creature cards in your graveyard.

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever you cast an Equipment or Adventure spell, add a quest counter.
Exile the top two cards of your library, then choose one of them. You may play that card until the end of your next turn.
Until end of turn, target creature you control gets +1/+0 and gains double strike, vigilance, and indestructible.

When Verdant Curtain Mascot enters, choose one —
• You gain 2 life.
• Proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

Auditioning for a color causes you to create a 1/1 colorless Construct Actor creature token, then create one of the audition's Role tokens.

You may play basic land cards you own from outside the game.

Target creature gets +3/+3 and gains trample until end of turn.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

Remove a +1/+1 counter from a creature you control: Regenerate Verendas Brawler. (The next time this creature would be destroyed this turn, it isn't. Instead tap it, remove all damage from it, and remove it from combat.)

Codex — Heraldry; Whimsy; Villainy; Creativity; Brutality. (As this enters, conjure its contents into a shuffled face-up additional library.)
You may spend mana as though it were mana of any color to cast this codex's contents.
Spells you cast are all colors.

Verse of Fire deals 2 damage divided as you choose among up to two targets.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Vessel of Lost Souls envisions a creature card, you may have it become a copy of that card until end of turn.

Whenever a creature attacks you or a planeswalker you control, that creature's controller mills a card.

{2}, {T}, Sacrifice Vial of Dragonfire: It deals 2 damage to target creature.

Return target spell to its owner's hand. If there are three or more colors among permanents you control, you may counter that spell instead.

All creatures get -X/-X until end of turn. X can't be 0.
Whenever a creature dies this turn, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

Choose one —
• Destroy target artifact or enchantment with mana value 3 or less.
• You gain 3 life. Draw a card.

Deathtouch, protection from legendary
Vielle, Undercity Wayfarer has all loyalty abilities of permanents on the battlefield that cost +1, +0, or -1. (Before cost changes. Add or remove loyalty counters from Vielle to pay their loyalty costs.)