msem-instigator

Harmony — Tap target creature. That creature doesn't untap during its controller's next untap step.
When Chilling Musician enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Motley — This spell costs {3} less to cast as long as there are five or more names among nonland permanents you control.
Destroy all creatures.

At the beginning of your draw step, draw an additional card. If you control three or more artifacts, draw two additional cards instead.
At the beginning of your end step, discard your hand.

Whenever Guided Medic attacks, upgrade it. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Lifelink

Exile target creature. You gain 2 life.

Whenever Fallacy's Channeler becomes untapped, each player sacrifices a creature.
{T}, Pay 1 life: Fallacy's Channeler deals 1 damage to any target.

Each player may play an additional land on each of their turns.
Whenever a land enters, each player may draw a card.

Flash
When Master of Disorientation enters, you may choose new targets for target instant or sorcery spell. Then proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

({T}: Add {R}, {W}, or {B}.)
Desolate Dominion enters tapped.

When this creature enters, draw a card.

Whenever you make first contact, create a 1/1 white Bird creature token with flying. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)
Whenever three or more creatures you control deal combat damage to a player, create a token that's a copy of another target permanent you control.

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Draw X cards. Then if X is 2 or greater, you may discard any number of cards. For each card discarded this way, create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

{B}, {T}, Discard a card: Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Spirited (When this enters, you may activate one of its activated abilities without paying its cost.)
{5}, {T}, Discard a card: Create a 0/0 colorless Construct artifact creature token with “This creature gets +1/+1 for each artifact you control.” It can't block this turn.

At the beginning of combat on your turn, Ruination's Hand gains flying until end of turn if a creature you control or a creature card in your graveyard has flying. The same is true for first strike, double strike, deathtouch, hexproof, haste, indestructible, lifelink, menace, reach, trample, and vigilance.

Flash
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.)

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.)

As this artifact enters, choose a creature type.
{T}: Put a muster counter on this artifact.
{T}: You may put a creature card of the chosen type with mana value equal to the number of muster counters on this artifact from your hand onto the battlefield.

Descended Hollow enters tapped.
{T}: Add {U} or {B}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Equipped creature gets +2/+2 and has flying and lifelink.
When equipped creature deals combat damage to a player, unattach Shionoshio, Ocean's Vow, then transform it.
Equip {W}{U}
Shionoshio can be your commander.

Flying, vigilance, deathtouch, lifelink

[+1]: Tap up to one target creature. Azun, Sheriff of Daisite deals 1 damage to each opponent.
[–1]: Exile another target nonland permanent until Azun, Sheriff of Daisite leaves the battlefield.
[–7]: Detain each permanent target opponent controls. (Until your next turn, those permanents can't attack or block and their activated abilities can't be activated.)

Scavenger Holdout enters tapped.
When Scavenger Holdout enters, you may pay {3}. If you do, create two 1/1 green Scout creature tokens.
{T}: Add {C}.

Exile target creature.
Draw a card.