msem-instigator

Reveal the cards in your library. Target opponent chooses three nonland cards with different names from it. You put the chosen cards into your hand. Then shuffle.

Whenever a creature you control phases in, it gets +2/+2 until end of turn.

When Three Seas Squire enters, target creature or Vehicle gets +2/+1 until end of turn.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Draw three cards.
5 | Add {W}{U}{B}{R}{G}. You can cast only one more spell this turn.

Target creature gets -3/-3 until end of turn. Its controller loses 3 life. You mill three cards.

When Threshing Sundew enters, merge up to one target creature card in your graveyard under it. Threshing Sundew has that card's abilities.
When Threshing Sundew dies, return all other cards merged with it to their owner's hand.

Vigilance, trample
When Threshold Guardian enters, return a creature you control to its owner's hand.

Haste
At the beginning of combat on your turn, create two nonlegendary token copies of Thrice-Clawed Troika. Then for each creature token created this way, create token copies of each permanent attached to Thrice-Clawed Troika and attach them to that creature token. Exile all tokens created this way at end of combat.

As an additional cost to cast this spell, discard a card.
Draw two cards.

Whenever Thrinax Sporemother or another nontoken creature you control dies, create a 1/1 green Saproling creature token.
Whenever a creature card is exiled from your graveyard, create a 1/1 green Saproling creature token.

{T}: Add one mana of any type that a land you control could produce.
Augmented — At the beginning of your end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, untap Thriving Budling and put three +1/+1 counters on it.

Trample, haste
Thriving Hydra enters with four +1/+1 counters on it.
When Thriving Hydra enters, for each other creature you control, put X +1/+1 counters on that creature, where X is four minus its power.
Whenever Thriving Hydra attacks, double the number of +1/+1 counters on each creature you control.

As an additional cost to cast this spell, sacrifice a land.
Creatures you control get +1/+1 and gain trample until end of turn for each land you control.

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.)
Hexproof
At the beginning of your upkeep, put a +1/+1 counter on this creature.

Trample
Once each turn, if one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on that creature instead.

Each creature you control enters with an additional +1/+1 counter on it.
Each planeswalker you control enters with an additional loyalty counter on it.

Whenever a permanent an opponent controls becomes the target of a spell you control, put a progress counter on Throne of the West.
[PROGRESS 2+] {T}: Gain control of target permanent until end of turn. Untap it. It gains haste until end of turn.
[PROGRESS 5+] You can't lose control of permanents.

Exile any number of target creatures and/or planeswalkers you control. You gain 1 life for each card exiled this way, then return them to the battlefield under your control.

Target player mills three cards for each poison counter they have.

The next creature spell you cast this turn may be cast as though it had flash and costs {1} less to cast. If it entering the battlefield causes a triggered ability of it to trigger, that ability triggers an additional time.

Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Flashback—{B}, Pay 2 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Each player sacrifices a creature with mana value X or greater.
Return up to one target creature card with mana value X or less from your graveyard to the battlefield.

When Through the Dust enters, it becomes an Aura with enchant creature. Reveal the top seven cards of your library, put a creature card revealed this way onto the battlefield and attach Through the Dust to it. Then put the rest on the bottom of your library in any order. When Through the Dust is no longer on the battlefield, enchanted creature's controller sacrifices it.
Mirage {1}{U}{U}{U} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

You may sacrifice a land. If you do, search your library for a land card, put that card onto the battlefield, then shuffle.
Inscribe {3}{G} ({3}{G}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Whenever equipped creature attacks, you may unattach Throwing Stones. When you do, target creature can't block this turn.
Equip {3}