msem-instigator

Tomb of Great Drakes enters tapped.
{T}: Add {U}.
{2/U}{2/U}: Tomb of Great Drakes becomes a 2/2 blue Elemental creature with flying until end of turn. It's still a land.

{T}: Add {C}.
{1}: Tomb of Shifting Sands becomes a copy of target land card in any graveyard, except it has this ability and it's a Desert in addition to its other types. (This effect lasts indefinitely.)

Tomb of the Roseblade enters tapped.
{T}: Add {C}.
{X}, {T}, Sacrifice Tomb of the Roseblade: Search your library for an Equipment card with mana value X or less, put it onto the battlefield, then shuffle. Activate only as a sorcery.

Whenever a nontoken creature dies, you may exile that card. If you do, return each other card exiled with Tome of the Lidless Gaze to its owner's graveyard.
At the beginning of your upkeep, if you control no Eyes, create a token that's a copy of a card exiled with Tome of the Lidless Gaze except it's a 2/2 Eye Horror with flying in addition to its other types.

Equipped creature has “Whenever this creature attacks, you may sacrifice Torch of Phoenixfire. When you do, Torch of Phoenixfire deals 3 damage to any target.”
Equip {1}

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.)

({T}: Add {U} or {R}.)
Torrid Geysers enters tapped unless you control two or more basic lands.

Torrid Path enters tapped unless you control one or fewer other lands.
{T}: Add {R} or {W}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Enchant creature
Enchanted creature gets +3/+3 and has trample.

{T}: Add {C}.
{2}, {T}: Draw a card. Activate only if you have no cards in hand.

Towering Boughs enters tapped.
{T}: Add {R} or {G}.
{3}{R}{G}: Until end of turn, Towering Boughs becomes a 6/6 red and green Treefolk creature with with trample and “Whenever this creature attacks or blocks, torment yourself.” It's still a land. (To torment yourself, lose 3 life unless you discard a card or sacrifice a nonland permanent.)

Toxic Jungle enters tapped unless you have 15 or less life.
{T}: Add {B} or {G}.

As Toxic Spring enters, you may tap an untapped creature you control. If you don't, Toxic Spring enters tapped.
{T}: Add {U} or {B}.

Equipped creature gets +0/+2.
When equipped creature dies, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Equip {1}

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
{2}, Discard your hand: Unlock Traitor's Gambit. If the revealed card is red, put it into your hand. Otherwise, put it on top of your library.

Tranquil Cove enters tapped.
When Tranquil Cove enters, you gain 1 life.
{T}: Add {W} or {U}.

Tranquil Shrine enters tapped.
When Tranquil Shrine enters, if you don't control a legendary creature, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

({T}: Add {W} or {U}.)
Tranquil Stream enters tapped.

You may exile a land card from your hand rather than pay this spell's mana cost.

{T}: Add {C}.
{7}: Transplanted Citadel becomes a 6/6 Golem artifact creature until end of turn. It's still a land. This ability costs {1} less to activate for each artifact you control.

You may reveal creature cards with mana value 3 or less as you draw them. Once each turn, when you reveal a card this way, you may aetherize it. (To aetherize, create a token that's a copy of it, then exile that token.)

Whenever a creature attacks you or a planeswalker you control, that creature doesn't untap during its controller's next untap step.

At the beginning of your upkeep, you may exile a card from your hand. If you do, draw a card.
Whenever equipped creature deals combat damage to a player, you may put a card exiled with Travel Pouch into its owner's hand.
Equip {1}

{1}, Sacrifice Traveler's Amulet: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Treacherous Den enters tapped.
{T}: Add {B} or {R}.
{2}{B}{R}, {T}, Sacrifice Treacherous Den: Draw a card.