msem-instigator

Whenever a creature you control enters, Timid Thunderhorn gets +X/+X until end of turn, where X is that creature's power.

First mate — Each nonland card in your starting deck is an artifact, a Pirate, or has “artifact,” “Treasure,” or “Pirate” in its printed rules text. (If this card outside the game is your chosen first mate, you may swap it with a card in your opening hand.)
Whenever Tinbeard of the Brine attacks, each opponent loses X life and you gain X life, where X is the number of artifacts you control plus the number of Pirates you control.

{3}: Put a +1/+1 counter on Tinkerer's Assistant.

This spell has flash as long as you control a Soldier.
When Tinyvale Watchkeep enters, untap target creature.

Advance {3}{B}{B} (Cast this for {3}{B}{B} to advance it as it enters. {3}{B}{B}: Advance this as a sorcery.)
Whenever Tireless Archivist advances, search your library for a card, put it into your hand, then shuffle.

When Titan of Lake Vasil enters, untap up to four target permanents.
{3}{U}: Draw a card.

Whenever Titanic Hardshell deals combat damage to a player, draw a card.
{2}{G}: Titanic Hardshell gains trample until end of turn.

First strike
Noncreature spells with mana value 4 or greater cost {1} more to cast.

Tizzanier Tidehunter can't be blocked as long as you control another Merfolk.

{2}{B}, Exile a card from your graveyard: Tomb Creeper gets +2/+2 until end of turn.

Creatures with power 4 or greater can't attack or block unless their controller pays {2} for each of those creatures.

Flying
Whenever another creature you control enters from a graveyard or you revive a creature token, Tomb Scavenger gets +2/+0 until end of turn.

When Tombstone Looter enters, you may draw a card. If you do, discard a card.
Unearth {1}{U} ({1}{U}: 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.)

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.

Ward {2}
Even numbered spells you cast each turn costs {2} less to cast. (The second, fourth, sixth, etc.)

{2}{B}: Return Torchlight Tormentor from your graveyard to your hand. If you do, each opponent loses 1 life.

Winnow (Damage dealt to this creature also causes you to lose that much life.)
Sacrifice Tormented Echo: Target creature gains winnow until end of turn.

Glorious end — When Toros the Warchief dies, if it was tapped, return it to the battlefield at the beginning of the next end step.
Attacking creatures you control have deathtouch.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Vehicle becomes an artifact creature until end of turn.)

{G}, {T}: Add one mana of any color. When a creature enters this turn, if that mana was spent to cast it, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Tortle Traveler enters tapped.
When Tortle Traveler enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Whenever Tortle Veteran or another Turtle you control enters, that creature explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

{1}{W}, Sacrifice Town Elder: Return target artifact or enchantment card from your graveyard to your hand.

Deathtouch

Whenever Toxic Miscreant deals combat damage to a player, that player discards a card.