msem-instigator

{5}{U}{U}: Thassa's Tidebringer can't be blocked this turn. This ability costs {1} less to activate for each creature you control with a counter on it.

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of each combat, you may tap or untap another target nonland permanent.
{2}{U}: Create a 1/1 blue Merfolk Rogue creature token with “{T}: Draw a card, then discard a card.”

Thawing Valley enters tapped unless you control a basic land.
{T}: Add {G} or {U}.

Menace
When The Anguilahydra enters, draw X cards and put X +1/+1 counters on The Anguilahydra, where X is the number of enchantments you control.

{T}: The next time you would draw a card this turn, instead search your library for a card, put it into your hand, then shuffle. Activate only as a sorcery.

Menace
Whenever you cast a spell from your graveyard, The Selhoff Twins deals damage equal to that spell's mana value to any target. Then copy that spell. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Flying, menace, trample
When The Wickerscreech of Gatstaf dies, destroy target nonland permanent an opponent controls.
Foreshadow {13}. This costs {1} less for each nonland card in your graveyard. (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

Trample
Stampede — Whenever Thoctar Yearling and a creature with greater power attack, put a +1/+1 counter on Thoctar Yearling.

{T}: Add {G}. If there are three or more creature cards in your graveyard, add {G}{G} instead.

Flash
When Thraben Redeemer enters, choose up to one target permanent card in your graveyard that was put there from the battlefield this turn. Return it to your hand.

This spell costs {2} more to cast for each target beyond the first.
Choose one or more —
• Counter target creature or planeswalker spell with mana value 4 or less.
• Exile target permanent you control, then return that card to the battlefield under your control.
• Target player draws two cards, then discards two cards and mills two cards.

Target creature gets -3/-3 until end of turn. Its controller loses 3 life. You mill three cards.

Whenever Thrinax Sporemother or another nontoken creature you control dies, create a 1/1 green Saproling creature token.
Whenever a creature card is exiled from your graveyard, create a 1/1 green Saproling creature token.

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

Whenever Thunderwolf attacks, exile the top card of your library. You may play that card this turn.

Choose one —
• Draw three cards, then discard a card.
• The owner of target nonland permanent puts it on the top or bottom of their library.

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.

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.

Colossal 2—{6}{U} (You may cast this for its colossal cost to have it enter with two +1/+1 counters; or pay {6}{U} as a sorcery: Put two +1/+1 counters on it if it has none.)
When Titanic Fathomclaw's colossal ability puts one or more counters on it, return target instant or sorcery card from your graveyard to your hand.

Enchant creature without flying
Enchanted creature gets +10/+0 and attacks each combat if able.

Flying
Tizerus Bats can't block unless you control another creature with flying.

Reach
You may have other creatures you control enter as a copy of any creature card in a graveyard with equal or lesser mana value.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever Topan Curemaster encourages a creature, you gain 1 life.

Torch Reveler gets +2/+0 as long as you control an artifact.