msem-instigator

Ominous Dragoncaller gets +1/+1 and has flying as long as you control a Dragon.

This spell costs {1} less to cast for each card in your graveyard.
Menace

Equipped creature gets +0/+3 and has menace. (It can't be blocked except by two or more creatures.)
Equip {1}

When Ominous Presence enters, search your library for a Curse card, reveal it, then shuffle. If it has mana value 4 or less, you may put it onto the battlefield. Otherwise, put it into your hand.
Ominous Presence gets +1/+1 for each Curse attached to your opponents.

Return target creature card from your graveyard to the battlefield tapped. Then create a token that's a copy of it, except it has haste. Sacrifice the token at the beginning of the next end step.

Post a bounty on target creature you don't control, then each opponent sacrifices a creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

I, II — Put your choice of a flying or hexproof counter on target creature you control.
III — Creatures you control with counters on them can't be blocked this turn unless defending player pays {3} and spells that target those creatures cost an additional {3} to cast until your next turn.
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Whenever a creature dies, put a +1/+1 counter on each creature you control with power less than it.
{3}{G}, Sacrifice a creature: Draw cards equal to the sacrificed creature's power.

This spell costs {G} less to cast if it targets a blue or black permanent.
Destroy target artifact, enchantment, or planeswalker.

This spell costs {1}{B} less to cast if it targets a green or white permanent.
Destroy target creature or planeswalker.

This spell costs {1}{U} less to cast if it targets a red or green spell.
Counter target spell.
Draw a card.

This spell costs {W} less to cast if it targets a black or red permanent.
Exile target nonland permanent with mana value 3 or less.

For each player, choose a creature or planeswalker that player controls. Each player sacrifices all creatures and planeswalkers they control not chosen this way.
Fuse (You may cast one or both halves of this card from your hand.)

Gain control of target creature until end of turn and untap it. Until end of turn, it gains haste and “Whenever this creature attacks, it deals 2 damage to itself.”

Return target creature card from your graveyard to the battlefield. Then up to one target opponent sacrifices a creature if you control an Angel, Demon, Faerie, or Spirit.

Spells your opponents cast that target Onigori, Ema's Shield cost {2} more to cast.
Whenever Onigori deals combat damage to a player, that player can't untap more than two permanents during their next untap step.

Onoran Runeglyphs enters tapped.
{T}: Add two mana in any combination of colors from among creatures you control.
Menagerie — {2}, {T}: Draw a card. Activate only if there are five or more creature types among creatures you control.

Flying
Creatures you don't control have “{T}: This creature fights Ontarachie Apex. Activate only as a sorcery.”

Germinate, then creatures you control that are Saprolings or have counters on them gain indestructible until end of turn. (To germinate, put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Whenever you draw a card, put a +1/+1 counter on Ontarachie Dryad.
Remove a counter from Ontarachie Dryad: Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

When Ontarachie Envoy enters, nourish, then germinate. (To nourish, put a +1/+1 counter on this creature or create a 1/1 white Citizen creature token. To germinate, put a +1/+1 counter on a creature you control or create a 1/1 green Saproling creature token.)

Vigilance (Attacking doesn't cause this creature to tap.)
Sacrifice a Fungus, Saproling, Plant, or Insect: Put a +1/+1 counter on Ontarachie Forager.

When Onward to War enters, draw a card, then choose a card name.
Whenever one or more creatures you control with the chosen name attack, look at the top four cards of your library. Put a creature or enchantment card with mana value 3 or less from among them into your hand. Put the rest on the bottom of your library in any order.

When Onya the Gilded dies, search your library for a planeswalker card with a different name, reveal it, put it into your hand, then shuffle.
[–1]: Draw up to two cards. For each of those cards, pay 1 life or discard a card.
[–2]: Creatures you control get +1/+1 until your next turn.
[–3]: Onya the Gilded deals 3 damage to any target and you gain 3 life.

Lifelink
Whenever a planeswalker dies, Onya's Chosen deals 3 damage to target creature or player.