msem-instigator

{T}: Add one mana of any color. Spend this mana only to cast a creature spell or activate an ability of a creature.
Whenever a creature you control becomes a Demigod or God, untap Terracotta Sage and it becomes a 4/4 Dragon with flying until end of turn.

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

When Tessellated Orb enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.
When Tessellated Orb dies, draw a card.

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.)
{0}: Unlock Tesseract Conjecture. If the revealed card shares a mana value with three or more permanents you control, cast it without paying its mana cost.

Whenever a creature you control dies, put a legacy counter on Testament to Heroism.
{T}: Add {C}.
{T}, Remove a legacy counter from Testament to Heroism: Add one mana of any color.

Thalassic Borough enters tapped unless you have 15 or less life.
{T}: Add {U} or {B}.

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

Your opponents play with their hands revealed.
Whenever you cast a spell with the same name as a card in an opponent's hand, draw two cards.

{T}: Add {C}.
{5}, {T}, Sacrifice The Aetherite Saloon: Each player discards their hand and draws seven cards.

Once each turn, if a triggered ability of another legendary permanent you control would trigger, you may have it trigger an additional time.

{T}, Pay 1 life: Add {U}.
{4}{U}{U}{U}, Exile The Aurora's Heart from your hand: Target player draws seven cards.

If you would look at or reveal one or more cards of a library, you may first search that library for that many cards, shuffle that library, then put those cards on top of it in any order.

Flying, haste
Whenever The Branded Usurper attacks, it deals 2 damage to any target.
If you would lose the game, instead exile The Branded Usurper. Your life total becomes 0. Until an opponent's next turn, you can't lose the game and you can't gain life. Take an extra turn after this one.

Flying
Whenever a creature attacks you or a planeswalker you control, put a -1/-1 counter on that creature.

{T}, Pay 1 life: Add {R}.
{6}{R}{R}, Exile The Court of Angels from your hand: Destroy all artifacts, creatures, and lands. They can't be regenerated.

Indestructible
At the beginning of your upkeep or when this creature transforms into The Divine Lovers, gain control of target permanent with mana value X or less until end of turn, where X is the number of creatures you control. Untap that permanent. It gains haste until end of turn.

Flying
Creatures you control have “{T}: Add {C} or one mana of any color.”
{X}: The Finest Specimen gets +X/+X until end of turn.

Vanishing 5
The High Prairies enters tapped.
{T}: Add one mana of any color.

Spirited (When this enters, you may activate one of its activated abilities without paying its cost.)
{3}, {T}: Create a colorless Equipment artifact token with “Equipped creature gets +1/+1” and equip {1}. Attach that token to a creature you control.

{T}: Add {C}.
{2}, {T}: Prevent all combat damage target creature would deal this turn.

At the beginning of your upkeep, reveal the top two cards of your library. An opponent chooses one. Put the chosen card into your hand and exile the other.
{4}, {T}: Put a card exiled with The Knowledge Hub into its owner's hand.

The Last Sacred Gate enters tapped.
While you're searching your library, you may play The Last Sacred Gate from your library. (You may only do so during your turn and if you have a land play remaining.)
{T}: Add {C}.

As The Mistake enters, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.
Unveil {5} ({5}: Transform this. Unveil only as a sorcery.)

[+1]: Add {W}{U}{B}{R}{G}.
[–1]: Exile the top three cards of your library. Until end of turn, you may play cards exiled with this permanent.
[–3]: Create a 5/5 Archon creature token that's all colors and has flying and “When this creature enters, it deals 5 damage to any target.”

{T}: Add {C}.
{2}, {T}: Choose a color, then choose one —
• Add one mana of that color for each token you control.
• Add one mana of that color for each permanent you control with one or more counters on it.