msem-instigator

Discard two cards, then draw a card for each card discarded this way. Night of Falling Stars deals damage equal to the total mana value of the discarded cards to each creature.

{T}: Add {C}.
{3}: Mill two cards, then return Midnight Keep from your graveyard to the battlefield tapped.

Haste
When Collapsing Star Viper enters, you may tap target permanent with mana value X or less.
At the beginning of your upkeep, return Collapsing Star Viper to its owner's hand.

{T}: Add {C}.
{4}, {T}, Sacrifice Eon Campfire: Destroy target artifact or nonbasic land.

{1}{B}, Mill three cards: Return Dredging Aberration from your graveyard to your hand.

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.)
{T}: Draw a card, then discard a card.

Other creatures you control get +0/+1.
Whenever a creature you control perseveres, you gain 1 life. (A creature perseveres when it survives damage.)

Sunlit Fissure enters tapped.
{T}: Add {G} or {W}.
{2}{G}{W}: Until end of turn, Sunlit Fissure becomes a 3/5 green and white Elemental creature with with vigilance and “Whenever this creature attacks or blocks, torment yourself.” It's still a land. (To torment yourself, lose 3 life unless you discard a card or sacrifice a nonland permanent.)

Each opponent sacrifices an artifact or enchantment.
Showcase {2}{G}{G} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Advance costs you pay cost {1} less.
You may activate advance abilities of permanents you control any time you could cast an instant.

Scry 2, then draw two cards. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Put a +1/+1 counter on target creature. It can't be blocked this turn.(Cast a copy of this spell once while this creature is on the battlefield.)

{T}, Pay 1 life: Add {U} or {R}.
{1}, {T}, Sacrifice Heist Headquarters: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice that creature at the beginning of the next end step.

Choose two. X can't be 0 —
• Create a token that's a copy of target creature you control with mana value X or less.
• Creatures target player controls get +0/+X and gain reach until end of turn.
• Put target noncreature, nonland permanent into its owner's library just beneath the top X cards of that library.
• Target player surveils X, then draws a card.

Flying
Menagerie — When Northrime Messenger enters, if there are five or more creature types among creatures you control, you may search your library for a Quest card, reveal it, put it into your hand, then shuffle.

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
When Renegade Spiritualist becomes renowned, create a 1/1 green Spirit creature token.

Whenever Fireheart Centaur attacks, you may pay {2}{R}. If you do, it gets +1/+0 until end of turn for each Centaur you control.

Target opponent reveals their hand. You choose a nonland card from it. If you can't, they discard a card. Otherwise, that player discards a card, then if they didn't discard the chosen card, you create a tapped Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Vigilance
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Whenever an opponent attacks you, create a tapped 1/1 white Soldier creature token with melee. Exile that token at the beginning of your next end step.

{1}{R}, {T}: Target creature gains shimmer until end of turn. (Whenever it attacks this turn, create a tapped and attacking token that's a copy of it. Exile that token at the beginning of the end step.)

{W}, Sacrifice Haunting Bard: Destroy target artifact or enchantment.

Whenever a creature you control assaults, put a +1/+1 counter on Devoted Nomad.

{1}{U}: Mercurial Merfolk gets +2/-2 until end of turn.
When Mercurial Merfolk dies, draw a card.

[+2]: Look at the top card of your library. If it's a permanent card with mana value less than the number of lands you control, you may put it onto the battlefield.
[–1]: Sacrifice a land. If you do, draw three cards.
[–7]: Destroy up to X target permanents, where X is the number of lands you control.