msem-instigator

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.

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.

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

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

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.)

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

Reach, deathtouch

Prismatic — Whenever you cast a multicolored spell, Thorny Bushwacker has base power and toughness 5/3 until end of turn.

Whenever a creature enters under an opponent's control, draw a card unless that player pays {1}.

When Thoughtgrinder enters, each player discards a card.
Unearth {1}{U}{B} ({1}{U}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the end step or if it would leave the battlefield. Unearth only as a sorcery.)

When Thoughtslick Engineer enters, each player discards a card at random.

Flash
When Threadripper Savant enters, put a stun counter on up to one target creature.

When Three Seas Squire enters, target creature or Vehicle gets +2/+1 until end of turn.

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
Trample

Vigilance, menace, trample, haste
Whenever you cast a spell, you may have Thunderous Avarice consume. If you do, put a +1/+1 counter on it. (To consume, sacrifice another creature or exile a creature card from your graveyard.)
Whenever an opponent casts a spell, they may have Thunderous Avarice consume. If they don't, put a +1/+1 counter on it.

Flash
Cycling {2} ({2}, Discard this card: Draw a card.)

When Thunderstep Ved enters, it deals 1 damage to any target.

Whenever Tide Crasher attacks, if you control another Merfolk, tap target creature defending player controls.

Embellish {3}{B} (If you cast this spell for {3}{B}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)
Tidehollow Lich can't block.
You may cast Tidehollow Lich from your graveyard as long as you control an artifact creature.

Menace, haste
Whenever Tiger of the Drums attacks, choose one —
• Exile target opponent's graveyard.
• You draw a card and lose 1 life.
• Torment each opponent. (They lose 3 life unless they discard a card or sacrifice a nonland permanent.)

Return target permanent to its owner's hand. If this spell wasn't cast from your hand, put that permanent on top of its owner's library instead.
Coalesce {9}{U} (You may cast this from your graveyard for {9}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Double strike (This creature deals both first-strike and regular combat damage.)
If three or more creatures are attacking you, you may cast Timely Commander as though it had flash.

First strike
If one or more creature tokens would be created under your control, for each of those tokens, you may create three 2/2 green Cat Warrior creature tokens instead.