msem-instigator

{T}: Add {C}.
{4}, {T}, Sacrifice Slyten Crystal Motherlode: Add {W}{U}{B}{R}{G}.

Flash
Enchant player
When Curse of Doubt enters, counter target spell enchanted player controls unless they pay {2}.
{4}{U}: Enchanted player mills three cards.

Eureka! (At the beginning of each end step, you get a research counter if you cast a spell this turn. Then if you have eight or more research counters, remove them and create a Masterpiece token of your choice.)
At the beginning of your first end step each turn, you get an additional end step after this step.

Whenever an enchantment you control enters, create a 1/1 colorless Construct Actor creature token.
Token creatures you control have vigilance.

Create a token that's a copy of target permanent you control, except it isn't legendary. Then put Picture Perfect on the bottom of its owner's library if you cast it from exile.
Leitmotif (If you cast this spell from your hand, exile it as it resolves. When you next cast a spell that shares a color with this card, you may cast this from exile without paying its mana cost.)

When Knight's Attendant enters, create a 2/2 white Knight creature token with vigilance.

Haste
Whenever Tailor of Terror attacks, you may exile a creature card from your graveyard. If you do, put a +1/+1 counter on Tailor of Terror.

Bustling Marketplace can't be sacrificed.
{T}: Add one mana of any type that a land you control could produce.
{0}: Bustling Marketplace's owner may draw a card. If they do, untap Bustling Marketplace and gain control of it until end of turn. Only your opponents may activate this ability and only once each turn during their turn.

Enchant creature
Enchanted creature gets +0/+2 and can block an additional creature each combat.

Harmony — You may pay {1}{G}. If you do, create a 3/3 green Beast creature token.
When Wildheart Chorister enters, harmonize. (Trigger up to one harmony of a permanent you control.)

Whenever you draw your second card each turn, put a +1/+1 counter on Ethereal Sneak.

Haste
Whenever Arpechian Tiger attacks, you may sacrifice a land. If you do, Arpechian Tiger deals 3 damage to target creature or planeswalker.

Draw a card for each creature you control.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Burning of Xiangyin Temple deals 5 damage to target creature or planeswalker. If you're in a renaissance, Burning of Xiangyin Temple deals 3 damage to that permanent's controller.

As Prairie Monastery enters, you may tap an untapped creature you control. If you don't, Prairie Monastery enters tapped.
{T}: Add {G} or {W}.

Put three -1/-1 counters on target attacking or blocking creature.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Discard up to two cards, then draw that many cards plus one.
3 | For each color of mana spent to cast this spell, add one mana of that color.

Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
Draw three cards.

When Bloodpact Collector enters, destroy target creature an opponent controls that was dealt damage this turn or has a -1/-1 counter on it.

You may cast spells as though they had flash.
Whenever you cast a sorcery spell, each opponent loses 3 life unless they discard a card or sacrifice a nonland permanent.

When Everything Is Going Great enters, create a 4/4 Elemental creature token that's all colors.
At the beginning of your end step, exile up to one other target nonland permanent you control, then return it to the battlefield under your control.

Flash
When Hexfang Ascetic enters, return target spell to its owner's hand.

When Spiked Burrower dies, if it didn't have a counter on it, return it to the battlefield under your control with a +1/+1 counter or a lifelink counter on it.

Two target creatures you control each get +2/+1 until end of turn.

Creatures can't attack you unless their controller pays {2} for each of those creatures.
Whenever a permanent is returned to a player's hand, create a 1/1 white and blue Bird creature token with flying.