msem-instigator

As Legacy Foundations enters, you may reveal a Plains or Swamp card from your hand. If you don't, Legacy Foundations enters tapped.
{T}: Add {W} or {B}.

At the beginning of your upkeep, Harvest the Stars deals 4 damage to any target.

Menace
Whenever you cast a spell from your graveyard, The Selhoff Twins deals damage equal to that spell's mana value to any target. Then copy that spell. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Repurposed Construct enters tapped.
{T}: Add {B} or {G}.
{B}{G}, {T}, Sacrifice Repurposed Construct: Conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Vanishing 3
Whenever a time counter is removed from Prayers of Release, you may put a -1/-1 counter on target creature.

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.)
{5}{R}: Sullivan's Courier gets +2/+2 until end of turn.

{1}{B}, Sacrifice another creature: Put a +1/+1 counter on Nemesis Eidolon. Draw a card. Activate only as a sorcery.

Target opponent reveals their hand, exiles each nonland card from it, then conjures a card named Data-Point into their hand for each card exiled this way. (It's a sorcery that costs {2} with “Draw a card.”)

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Aleud Bladedancer has hexproof as long as it's attacking.

Whenever Power of Redemption attacks, choose one —
• Remove all -1/-1 counters from all creatures you control.
• Untap all creatures you control.

[0]: Creatures you control gain haste until end of turn. Whenever a creature attacks this turn, put a loyalty counter on The Warrior Within.
[–1]: Exile the bottom two cards of your library. You may play one of them this turn.
[–6]: Untap each creature that attacked this turn. After this main phase, there is an additional combat phase.

Destroy up to X target artifacts and/or enchantments. If X is 3 or more, you gain twice X life. If X is 6 or more, create two X/X Elemental creature tokens that are all colors.

When you cast this spell, copy it for each Reflection creature you control. You may choose new targets for the copies.
Mirrorstorm deals 1 damage to any target and you gain 1 life.

Defender
Civilized — As long as you control an artifact, a creature, and an enchantment, Hauling Hippopotamus can attack as though it didn't have defender.

{T}, Sacrifice Decrepit Crags: Search your library for a Swamp or Mountain card and put it onto the battlefield tapped, then shuffle.

Artifact vision (Whenever this or another artifact you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Mechanomind Researcher envisions an artifact card, put a +1/+1 counter on it.

When Wilderness Forager enters, you may reappropriate. If you do, gain 6 life. Otherwise, gain 3 life. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)

{T}: Add {C}. Exile a card from your graveyard.
{3}: Until end of turn, Forgotten Temple becomes an X/X creature, where X is the number of cards exiled by it. It's still a land.
As long as a creature card with flying is exiled by Forgotten Temple, it has flying. The same is true for first strike, double strike, deathtouch, experience, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

Whenever a creature you control enters, you may gain 1 life.
{3}{W}: Populate. (Create a token that's a copy of a creature token you control.)

Draw X cards, then abound. (To abound, you may cast a spell that costs less than this from your hand without paying its mana cost.)

Menace
At the beginning of your end step, if Vartrossen Vandals didn't attack this turn, transform it.

When Graide, Voice of Autumn enters, create X 1/1 green Squirrel creature tokens.
Squirrels you control get +1/+0 and have haste.
Nonbasic lands your opponents control enter tapped.

Whenever you pay a tithe, you may pay {2}. If you do, each opponent loses 3 life and you gain 3 life.

When Brawlhost Escapee dies, create a Function token with “Target creature you control fights target creature you don't control.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

As an additional cost to cast this spell, sacrifice a creature.
Enchant creature
Enchanted creature gets +4/+4, has flying, and is a Demon in addition to its other types.