msem-instigator

The Urchin King's power and toughness are each equal to the number of cards in all graveyards.
Sacrifice a creature: The Urchin King gains lifelink and indestructible until end of turn.

{T}: Add {C}.
{1}, {T}, Sacrifice The Whisperwoods: Add two mana in any combination of colors.
At the beginning of each end step, if a player lost life this turn, return The Whisperwoods from your graveyard to your hand.

{T}: Draw a card. Activate only if Theoretical Scholar is embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Target creature gets +1/+3 and gains hexproof until end of turn.

Thicketed Path enters tapped unless you control one or fewer other lands.
{T}: Add {G} or {W}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Equipped creature gets +1/+0 and has “Whenever this creature deals combat damage to a player, draw a card.”
Equip {3}

Target opponent reveals their hand. You choose a nonland permanent card from it. That player discards that card.

Equipped creature gets +2/+0 and has deathtouch.
Equip Rogue or Assassin {1}
Equip {3}

{1}{B}: Target Knight or Soldier you control gains deathtouch until end of turn.

Flash
Thorn-Touch Abomination enters with X +1/+1 counters on it.

Thornwood Falls enters tapped.
When Thornwood Falls enters, you gain 1 life.
{T}: Add {G} or {U}.

Target creature gets +2/+0 and gains haste until end of turn.
Fabled {2}{R} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Equipped creature gets +1/+0 and has menace.
Equip {3}

Thriving Bluff enters tapped.
As Thriving Bluff enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

{T}: Add one mana of any type that a land you control could produce.
Augmented — At the beginning of your end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, untap Thriving Budling and put three +1/+1 counters on it.

Thriving Grove enters tapped.
As Thriving Grove enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Thriving Heath enters tapped.
As Thriving Heath enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Thriving Isle enters tapped.
As Thriving Isle enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Thriving Moor enters tapped.
As Thriving Moor enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Each creature you control enters with an additional +1/+1 counter on it.
Each planeswalker you control enters with an additional loyalty counter on it.

Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Flashback—{B}, Pay 2 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Each player sacrifices a creature with mana value X or greater.
Return up to one target creature card with mana value X or less from your graveyard to the battlefield.

Whenever equipped creature attacks, you may unattach Throwing Stones. When you do, target creature can't block this turn.
Equip {3}

Thunder Wave deals 3 damage to target creature or planeswalker.

Target creature gains hexproof and trample until end of turn. If Thunderous Charge was cast from exile, that creature gets an additional +4/+4 until end of turn.
Orchestrate {G}{G} (You may exile this card from your hand anytime you could cast a sorcery for its orchestrate cost. When you next resolve a spell, you may cast this from exile without paying its mana cost.)