msem-instigator

{3}{U}: Tap target creature. Activate only as a sorcery.
Cycling {2/U} ({2/U}, Discard this card: Draw a card.)

{T}: Add {C}.
{3}{B}: Until end of turn, Tzhai's Throne becomes a 2/2 creature. It's still a land. It gets +2/+2 if {R} was spent to activate this ability, gets +2/+2 if {G} was spent, and gets +2/+2 if {W} was spent.

This spell costs {1} less to cast for each Scarecrow you control.
Other creatures you control get +0/+2 and have vigilance.

Whenever Uncanny Allocator enters the battlefield or attacks, give any number of permanents and/or players with counters on them another counter of each kind already there.

Uncharted Haven enters the battlefield tapped.
As Uncharted Haven enters the battlefield, choose a color.
{T}: Add one mana of the chosen color.

When Uncovered Idol enters the battlefield, scry 1.
{1}, Sacrifice Uncovered Idol: Put a +1/+1 counter on target creature. Activate only as a sorcery.

{T}: Add one mana of any color.
{T}, Sacrifice Unicorn of the Vale: Add three mana of any one color.

When Unity Spheres enters the battlefield, create two 1/1 colorless Construct artifact creature tokens.
Tap two untapped creatures you control: Add two mana of any one color.

University Archive enters tapped.
When University Archive enters the battlefield, look at the top card of your library. You may put it into your graveyard.
{T}: Add {U} or {R}.

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

{T}, Pay 1 life: Add {U} or {B}.
{1}, {T}, Sacrifice Unlit Alley: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

When Unmarked Vials enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
{1}, {T}: Add one mana of any color.

Add X mana in any combination of colors, where X is the amount of mana spent to cast Unravel Shattered Worlds.
Coalesce {7} (You may cast this from your graveyard for its coalesce cost. If you do, put it onto the battlefield as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

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

Vanishing 2 (This permanent enters the battlefield with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
{T}: Add {C}.
When Unstable Footing is put into your graveyard from the battlefield, if it had no time counters on it, search your library for a basic land card, put it onto the battlefield, then shuffle.

When Unstable Orb enters the battlefield, draw a card.
{3}, {T}, Sacrifice Unstable Orb: It deals 2 damage to target creature.

{T}: Add {C}.
{T}, Sacrifice Untethered Spire: Choose target land card in your graveyard that was put there from the battlefield this turn. Return that card to your hand.

Untrekked Territory enters the battlefield tapped.
{T}: Add {B} or {G}.
When Untrekked Territory enters the battlefield, you may put a loyalty counter on a planeswalker you control.

Unzari Ruins enters the battlefield tapped.
{T}: Add {C}.
Tap five untapped creatures you control: Unzari Ruins becomes a 10/10 Construct artifact creature with trample until end of turn. It's still a land.

({T}: Add {B} or {R}.)
Urban Wastelands enters the battlefield tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

When Urn of Heroes enters the battlefield, you may search your library for a legendary card, put that card into your graveyard, then shuffle.
{T}: Add {C}.

({T}: Add {B} or {R}.)
As Vacated Bar enters the battlefield, you may pay {1}. If you don't, Vacated Bar enters the battlefield tapped.

When Vale Ruins enters the battlefield, you gain 1 life.
{T}: Sacrifice Vale Ruins: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Valley Falls enters the battlefield tapped unless you control two or more white and/or blue permanents.
{T}: Add {W} or {U}.

As Vanquisher's Banner enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.