msem-instigator

Exile target artifact or enchantment. Its controller creates a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Enchant creature
When Impish Delights enters, draw a card.
Enchanted creature gets +2/+0.

{T}: Add {C}.
{T}: Add {C}{C}{C}. Spend this mana only to pay advance costs.

Flying
When Imposing Sphinx enters, exile target nonland permanent an opponent controls until Imposing Sphinx leaves the battlefield.
At the beginning of your end step, if you gained life this turn, you may exile Imposing Sphinx, then return it to the battlefield under your control.

You may reveal a creature card you own from outside the game and put it into your hand.
The next spell you cast this turn may be cast as though it had flash. Exile Impromptu Escapade.

If a card would be put into your graveyard from anywhere, exile it instead.
If you would draw a card, return two cards from your graveyard to your hand instead. If you can't, you lose the game.

You may put a green creature card with mana value 4 or less from your hand onto the battlefield.
Ferocious — If you control a creature with power 4 or greater, that creature enters with two +1/+1 counters on it.

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Iron Warden enters with two -1/-1 counters on it.
When Iron Warden dies, you may put its -1/-1 counters on target creature.
{R}: Iron Warden gets +1/+0 until end of turn.

Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)
Whenever Irreguleopard deals combat damage to a player, permutate. (You may remove a counter from a creature you control. If you do, put two +1/+1 counters on a different creature you control.)

Trample, haste
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Put target creature or planeswalker on the bottom of its owner's library. Its controller may scry 1.

(Choose only one work as a sorcery to add its ability.)
When Juyu Offering Pool enters, reveal the top five cards of your library. You may put a noncreature card from among them into your hand. Put the rest on the bottom of your library in any order.
{1}{U}: Scales of Shara
Whenever you cast a noncreature spell, put a +1/+1 counter on target creature you control.
{6}{U}{U}: Eye of Shojiro
Whenever you cast a noncreature spell, create an 8/8 blue Kraken creature token.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
When Kantra of Avarice enters, target player draws two cards and loses 2 life.

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast enchantment spells.

This spell costs {1} less to cast for each permanent you control that's an artifact and/or a token.
When Kellythross's Collector enters, you may return another target nonland permanent to its owner's hand.

Until end of turn, you may play cards from your graveyard by paying 2 life in addition to those cards' costs.
If a card would be put into your graveyard from anywhere this turn, exile that card instead.

Prowess
Whenever Knight-Academic attacks, scry 1.

Krismite Shard enters tapped.
{1}, {T}, Sacrifice Krismite Shard: Aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

Bleed {1}{B}{R} (You may cast this spell for its bleed cost if an opponent has lost life this turn.)
At the beginning of each end step, if an opponent lost life this turn, draw two cards, then discard a card at random.

Flash
Enchant creature
As Legacy of Northrime enters, choose a creature type.
Enchanted creature gets +1/+4 and is the chosen type in addition to its other types.

Creatures you don't control get -1/-1.

Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.

Whenever another artifact you control enters, put a +1/+1 counter on Lightsteel Enforcer.

Trample
{2}{R}{G}: Creatures you control get +1/+1 until end of turn.