msem-instigator

Augmented — When you cast this spell, if it's your turn and you've spent {W}{U}{B}{R}{G} to cast spells this turn, copy it twice. You may choose new targets for the copies.
Thunder Road deals 3 damage to any target. You gain 3 life.

Flying
When Thunder Shrike enters, choose up to two target permanents. For each of those permanents, you may tap or untap it.

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

Create a 3/3 red Giant creature token with haste.
Creatures you control gain double strike until end of turn.

Vanguard — Whenever a creature you control attacks alone, it gets +1/+1 and gains menace until end of turn.

Whenever Thundering Towershell attacks, return a creature card with mana value 5 or less from a graveyard to the battlefield under your control. Trigger a death knell of that creature.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Attacking creatures get -3/-0 until end of turn.
3 | Thundering Wrath deals 1 damage to each of those creatures.

Flying
Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{R}{R}, {T}: Exile an instant card with mana value 3 or less from your graveyard, then cast a copy of a card exiled with Thunderlash Mystic without paying its mana cost.

Flash
Whenever Thundermane Fox enters or attacks, target creature you control gains double strike until end of turn.

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.

Primal {2}{R}{R} (During your turn, you may cast this spell for {2}{R}{R} instead of playing a land.)
Flying, prowess
At the beginning of your end step, if you didn't cast a spell this turn, sacrifice Thunderstride.

When Thunderwhirl Dancer enters, it gets +X/+X until end of turn, where X is the number of +1/+1 counters among creatures you control. Then it fights up to one target creature.

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

Creature tokens you control get +1/+1.
Whenever Thyra, Winter's Warden enters or attacks, you may pay {1}{G/W}. If you do, create Bruga, a legendary 2/2 green and white Wolf creature token.

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.

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

When this creature enters, return a creature you control to its owner's hand.
{2}{U}: This creature gets +2/-2 until end of turn.

Permanents you control gain indestructible until end of turn. Untap each creature you control.
Cycling {W} ({W}, Discard this card: Draw a card.)

Choose target creature you control and target creature you don't control. Flip a coin. If the coin comes up heads, put one of those creatures on top of its owner's library. Otherwise, put both of them on top of their owners' libraries.

Each opponent sacrifices a creature or planeswalker.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Vanishing 4 (This creature enters with four time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Remove a time counter from Tideshift Elemental: You may tap or untap target creature.

Once each turn, when a creature you control becomes tapped, you may untap that creature and tap up to one target creature.

Kicker {X}{U} (You may pay an additional {X}{U} as you cast this spell.)
When Tidetwister Mage enters, if it was kicked, return all other creatures with power X or less to their owners' hands.