msem-instigator

Treacherous Oasis enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}: Until end of turn, Treacherous Oasis becomes a Crocodile creature in addition to its other types. It can't be blocked this turn.
Scavenge {1}{U}{B}

{T}: Add {C}.
{3}, {T}, Sacrifice Treasure Beach: Create three Treasure tokens. (They have “{T}, Sacrifice this artifact: Add one mana of any color.”)

Whenever Treasure Hauler attacks, draw a card.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Vehicle becomes an artifact creature until end of turn.)

Untap all other artifacts you control during each other player's untap step.
{T}: Untap another target permanent.

As Tree of Timelines enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}, {G}, or {U}.

Equipped creature has menace.
Whenever equipped creature attacks, look at the top two cards of your library. Put any number of them into your graveyard and the rest back on top of your library in any order.
Equip {2}

{T}, Pay 1 life: Add {G}.
{T}, Pay 1 life, Sacrifice Tropical Grove: Search your library for a Forest card, put it onto the battlefield tapped, then shuffle.

(Transform this if it's not attached to a creature. Pay {2}{W} as a sorcery to unattach it.)
Enchant creature you control
Trusty Steed's rider gets +2/+2.

Tsubasa's Redoubt enters tapped.
When Tsubasa's Redoubt enters, you may mill two cards.
{T}: Add {W} or {B}.

Hexproof
Whenever this creature transforms into Tsunami Titan or attacks, you may return target creature to its owner's hand.

Tumblewalker has vigilance as long as you control another Scarecrow.

{2}, {T}, Sacrifice Tunnel Map: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Twisting Fissure enters tapped.
{T}: Add {U} or {R}.
{1}, {T}: Add one mana of any color.

You may play Typhoon Caverns from your graveyard as long as seven or more cards are in your graveyard.
Typhoon Caverns enters tapped.
{T}: Add {U} or {B}.
Cycling {1}{U}{B} ({1}{U}{B}, Discard this card: Draw a card.)

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

Trample, haste
When Tyrants of Bundan enters, tap all lands target player controls. They don't untap during their controller's next untap step.

{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.

Spirited (When this enters, you may activate one of its activated abilities without paying its cost.)
{5}, {T}, Discard a card: Create a 0/0 colorless Construct artifact creature token with “This creature gets +1/+1 for each artifact you control.” It can't block this turn.

Unbound Spirit can't be blocked.
When you attain Unbound Spirit, tap target creature. That creature doesn't untap during its controller's next untap step.

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

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

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

Enchant creature
Enchanted creature has first strike. (That creature deals combat damage before creatures without first strike.)

Flying, vigilance
When you attain Unfallen Angel, target opponent discards a card.

Unfettered Noble can't be blocked unless defending player pays 3 life, discards a card, or sacrifices a nonland permanent for each creature they control that's blocking it.
Sacrifice a nonland permanent: Unfettered Noble gains indestructible until end of turn.