msem-instigator

Rhapsody {4}{U}{U} (Pay {4}{U}{U} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Whenever you cast a noncreature spell, Triumvirate Inductee gets +1/+1 until end of turn. Then if its power is 4 or greater, you may tap or untap target permanent.

Triumvirate Infiltrator has flying as long as you control another Elemental.

Each player chooses three permanents they control, then returns the others to their owners' hands. Each player loses all unspent mana.
Exile Turn the Record Over.

Create two 1/1 blue Elemental creature tokens with flying.
Reconstruct {7}{U} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

Rhapsody {4}{U}{U} (Pay {4}{U}{U} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
When Unstable Prophet enters, surveil X, where X is its power. (Look at the top X cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

When Wandering Visionary enters, draw a card.
{W}{U}{B}{R}{G}: Create a 1/1 blue Elemental creature token with flying.

When Abomination Broodmother dies, create a 3/2 green Horror creature token.

Destroy target creature or planeswalker.
Crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

At the beginning of your upkeep, you may pay 2 life. If you do, crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)

Whenever you cast a noncreature spell, each opponent loses 1 life.
{4}, Exile Arisen Psion from your graveyard: Draw a card.

Exile target creature or planeswalker. You gain 4 life.

You draw two cards and you lose 2 life.
Reconstruct {3}{B} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

When Debaser of Truth enters, if you control three or more Horrors, each opponent discards two cards.
Other Horror creatures you control get +1/+1.

Desperate Android enters tapped.
Whenever another artifact you control dies for the first time each turn, return Desperate Android from your graveyard to your hand.

Doom deals 3 damage to any target and you gain 3 life.
Reconstruct {3}{B}{B} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)
You may cast Doom from exile by paying {4}{B}{B}{B} rather than its mana cost. If you do, shuffle it into your library instead of putting it anywhere else as it resolves.

Deathtouch
When Doomed Explorer dies, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Each player sacrifices a creature.
Reconstruct {5}{B}{B}{B} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

Choose a color. Target player reveals their hand and you choose a card of that color from it. If you do, that player discards that card and you lose 1 life.

As Extinction Specialist enters, note two creature types.
Whenever Extinction Specialist enters or attacks, choose one of the noted creature types. Creatures you don't control of the chosen type get -1/-1 until end of turn.

Whenever you cast a black spell, put a +1/+1 counter on Flenser's Lieutenant.
{B}{B}: Return Flenser's Lieutenant from your graveyard to your hand.

Whenever Fleshwarper or another Horror you control dies, each opponent loses 1 life and you gain 1 life. You may mill a card.

Trample
When Ghastly Progenitor enters, each opponent reveals their hand. Choose two nonland cards revealed this way. Their owners discard those cards.

Target player discards two cards. Then exile that player's graveyard.

Target creature gets -4/-4 until end of turn.

Menace
Augmented — When Gravitational Ripper enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, target opponent sacrifices a creature. If they can't, they discard a card.