msem-instigator

Prowess
Whenever you cast a noncreature spell, audition for blue or for red. (Create a 1/1 Construct Actor creature token, a Wizard Role giving 2/2 and prowess, a Warlock Role giving 2/1 and flying, or a Warrior Role giving 3/2 and trample. Roles replace older ones.)

(As this Discovery enters and after your draw step, add a progress counter. Stop after you've discovered.)
I, II — Look at the top five cards of your library. Put up to one creature card with mana value 2 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Discovery — At the beginning of combat on your turn, tap target creature an opponent controls.

As Theodore Harper, Head Librarian enters, choose Fact or Fiction.
• Fact — Permanent spells you cast cost {1} less to cast. This effect can't reduce the amount of mana a spell costs to cast to less than one mana.
• Fiction — When Theodore Harper enters, return a permanent card 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.)

Flying, haste
Thermal Surger can't block.
When Thermal Surger enters, you may sacrifice a land or exile a land card from your graveyard. If you do, put a +1/+1 counter on Thermal Surger.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
At the beginning of your upkeep, create a token that's a copy of the enspirited card. It gains haste until end of turn. Exile it at the beginning of the next end step.

If a source you control would deal damage this turn, it deals double that damage instead.
Coalesce {7}{R}{R} (You may cast this from your graveyard for {7}{R}{R}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Haste

{2}{R}: Thespian Soldier gains first strike until end of turn.

Vanishing 3 (This permanent enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a time counter is removed from Thespian's Finale, create a token that's a copy of target creature. Sacrifice that token at the beginning of your next upkeep.

When Thespian's Page enters, return target instant or sorcery card from your graveyard to your hand.

Flying
Whenever Theurgic Flock deals combat damage to a player, if it doesn't have a +1/+1 counter on it, put a +1/+1 counter on it.

When Theurgist of the Depths enters, for each card type, you may exile a card of that type from your graveyard. Target opponent separates those cards into two piles. Put all cards from the pile of your choice into your hand.
Recite {B}{G}{U} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

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.)

Whenever Thicketkeeper perseveres, add {G}{G}. Until end of turn, you don't lose this mana as steps and phases end. (A creature perseveres when it survives damage.)

Reach
Whenever Thicketwalker attacks, you may tap or untap target land.

Flying
When Thief of Mortals deals combat damage to a player, as long as you control Thief of Mortals, gain control of target nonland permanent that player controls, and that permanent doesn't untap during its controller's untap step. Tap it.
At the beginning of each end step, if you control five or more permanents you don't own, you win the game.

Choose two —
• Scry 3, then you may mill up to three cards.
• Each opponent loses 3 life.
• You draw a card and you lose 1 life.
• Return a creature card from your graveyard to your hand.

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}

Search your library for a nonland card not named Thin the Veil, exile it, then shuffle. If it has mana value less than or equal to the number of card types among cards in your graveyard, you may cast it without paying its mana cost. If you don't, put it into your hand.

First strike
Other Foxes you control get +1/+1.
Whenever a Fox you control becomes blocked, it deals 1 damage to each creature blocking it.

When Third Legion Rider enters, if you control an embattled creature, tap target creature an opponent controls. It doesn't untap during its controller's next untap step. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Draw three cards. Then discard two cards unless you discard a card that has the same name as a permanent you control or a card in your graveyard.