msem-instigator

{4}{W}{W}: Create a 4/4 white Angel creature token with flying.
{2}{W}{W}: Populate. (Create a token that's a copy of a creature token you control.)

When Traversing Bulkvine enters, search your library for three land cards with different names and reveal them. An opponent chooses one of them. Put that card into your graveyard and the rest into your hand, then shuffle.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast your first instant or sorcery spell each turn, copy that spell. You may choose new targets for the copies.

Haste
When Treasure Haulers enters, you may salvage an artifact card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

As long as you control three or more artifacts, Treasury Master gets +2/+0 and has slipstream. (This creature can't be blocked as long as only creatures with slipstream are attacking.)

{2}{B}, Sacrifice a creature: Draw a card.

When Trenchbottom Mariners enters, you lose 3 life, mill three cards, and create a Treasure token.
Whenever Trenchbottom Mariners attacks, you may cast a permanent card from your graveyard by sacrificing another artifact in addition to paying its costs.

Trample
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Tribal Guard mentors a creature, that creature gains trample until end of turn.

{4}{G}{G}, Exile six other cards from your graveyard: Return Trifold Atrocity from your graveyard to the battlefield with three +1/+1 counters on it. Activate only as a sorcery.

Whenever an opponent casts their first spell each turn, that player may pay {1}. If they don't, you may create a Treasure token and you may draw a card.

Flying
When Trove Keeper dies, create two Treasure tokens.

Harmony — Search your library for a basic land or Desert card, reveal it, and put it into your hand. Then shuffle.
When Trumpeting Pathmaker enters, harmonize. (Trigger up to one harmony of a permanent you control.)

Whenever Trusted Comrade and at least one other creature attack, create a 1/1 white Soldier creature token that's tapped and attacking.

Whenever a creature dealt damage by Truth Extractor this turn dies, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Flying
Whenever you tap a Mountain for mana, add {R} and that land deals 1 damage to you.
Whenever you tap a non-Mountain land for mana, that land deals 1 damage to Tseng, Warden of the Peak.

Trample, hexproof
Renown 4 (When this creature deals combat damage to a player, if it isn't renowned, put four +1/+1 counters on it and it becomes renowned.)
{1}{G}: Target creature blocks Tsolmon, the Huntress this turn if able.

Tumblewalker has vigilance as long as you control another Scarecrow.

Reach, deathtouch

Whenever Twilight Walker perseveres, target creature doesn't untap during its controller's next untap step. (A creature perseveres when it survives damage.)

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Other creatures you control have base power and toughness equal to this creature's base power and toughness.

When Twinforged Golem enters, create a 3/3 colorless Golem artifact creature token.

{1}, Sacrifice another creature: Crystallize. Activate only as a sorcery. (Put a +1/+1 counter on a creature you control or create a Treasure.)
{W}{U}{B}{R}{G}: Target creature gets +3/+3 and gains trample until end of turn. Activate only as a sorcery.

Double strike
Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Engage (This creature must be blocked each combat if able.)

Creatures you control dying cause abilities of that creature to trigger as though that creature entered.
{2}{W}{B}, Sacrifice another creature: Destroy target nonland permanent.

Double strike
Whenever an Equipment you control enters, create a 3/3 white Archon creature token with flying and attach that Equipment to that token.