msem-instigator

[+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.”

The Urchin King's power and toughness are each equal to the number of cards in all graveyards.
Sacrifice a creature: The Urchin King gains lifelink and indestructible until end of turn.

Whenever The Winged Steed attacks, create a 4/4 red Dragon creature token with flying that's tapped and attacking. Exile that token at end of combat.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

(As this Discovery enters and after your draw step, add a progress counter. Stop after you've discovered.)
I, II — Look at the top five cards of your library. Put up to one creature card with mana value 2 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Discovery — At the beginning of combat on your turn, tap target creature an opponent controls.

Target opponent reveals their hand. You choose a nonland permanent card from it. That player discards that card.

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.

Flying
Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{R}{R}, {T}: Exile an instant card with mana value 3 or less from your graveyard, then cast a copy of a card exiled with Thunderlash Mystic without paying its mana cost.

Embellish {3}{B} (If you cast this spell for {3}{B}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)
Tidehollow Lich can't block.
You may cast Tidehollow Lich from your graveyard as long as you control an artifact creature.

Instant and sorcery spells you control have leitmotif. (Exile that spell as it resolves if you cast it from your hand. When you next cast a spell that shares a color with that card, you may cast it from exile without paying its mana cost.)

Your opponents can't search libraries unless they pay {2}.
[+2]: If an opponent has more life than you, you gain 2 life.
[0]: If an opponent controls more creatures than you, you create two 1/1 white Gnome creature tokens.
[–4]: Search your library for a creature card with mana value 2, put it onto the battlefield, then shuffle.

Search your library for a land card, put it onto the battlefield tapped, then shuffle.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, untap that land.

When Trident of Benediction enters, create two 1/1 white Merfolk creature tokens.
Equipped creature has vigilance and “Whenever this creature attacks or blocks, creatures you control get +1/+1 until end of turn.”
Equip {2}

{T}, Pay 1 life: Add {G}.
{T}, Pay 1 life, Sacrifice Tropical Grove: Search your library for a Forest card, put it onto the battlefield tapped, then shuffle.

Return all creature cards from your graveyard to the battlefield, then exile all but one of them.

Flash
When Tsang Jin, Master of the Jade Sea enters, put target land card from a graveyard onto the battlefield under your control.

Flash
Flying
When Turela, Defiant Angel enters, exile all other creatures you control. Return them to the battlefield under their owner's control at the beginning of the next end step.

Whenever a creature you control enters, if it wasn't cast, you gain life equal to that creature's toughness and may draw a card.
[+2]: Return up to one target creature card from your graveyard to the battlefield.
[–3]: Create an 8/8 blue Kraken creature token.
[–9]: Each player exiles all creature cards from their graveyard, then sacrifices each creature they control. Put each creature card exiled this way onto the battlefield under your control.

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.

Flying
When Tyrant of Tributes enters, target opponent sacrifices X permanents, where X is half the number of permanents they control, rounded up. You gain X life.

Concord — As long as there are four or more card types among permanents you control, you may cast the first spell you cast each turn without paying its mana cost.

When Undying Lich dies, create a 6/3 black Zombie Horror creature token with menace and “When this creature dies, create an 8/5 black Elder Demon Horror creature token with flying, deathtouch, and menace.”

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Create three 1/1 colorless Servo artifact creature tokens.
Exile Unending Armies. At the beginning of your upkeep, if you have more life than each opponent, you may cast it without paying its mana cost. Otherwise, put it into your graveyard.

Search your library for a card, reveal it, then shuffle and put that card on top of it. If you revealed a noncreature card this way, each opponent loses 2 life and you gain 2 life.

When Unity Spheres enters, create two 1/1 colorless Construct artifact creature tokens.
Tap two untapped creatures you control: Add two mana of any one color.