msem-instigator

Colossal 3—{5}{U} (You may cast this for its colossal cost to have it enter with three +1/+1 counters; or pay {5}{U} as a sorcery: Put three +1/+1 counters on it if it has none.)
When Omendiver's colossal ability puts one or more counters on it, scry 3.

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

Prowess
When One of Purpose enters, if you cast it, create a Function token with “If you cast this spell from your hand, exile it. You may cast it from exile until the end of your next turn.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

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

If you would germinate, instead create a 1/1 green Saproling creature token, then put a +1/+1 counter on a creature you control.
{2}{W}{W}: Germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

When Ophorio Scavenger enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Ophorio Scavenger gets +1/+1 as long as you control three or more artifacts.

Whenever you cast a noncreature spell, creatures you control get +1/+1 until end of turn.

Whenever you sacrifice an Idol, put a +1/+1 counter on Orchard Botanist.

Oreskos Warden has lifelink as long as you control an enchantment.

{2}{W}: Ornate Legionnaire gains first strike until end of turn.

You may cast spells as though they had flash.

Primal {1}{G}{G} (During your turn, you may cast this spell for {1}{G}{G} instead of playing a land.)
When Orria's Ward enters, if you played a land this turn, draw a card. Otherwise, put two +1/+1 counters on it.

{T}, Discard a card: Draw a card.
{2}{R}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy. Activate only if you have four or more instant and/or sorcery cards in your graveyard.

Deception {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Oshiruko Conspirator deals combat damage to a player, you may discard a Rogue card. If you do, search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Deception {2}{U} ({2}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When Oshiruko Silencer enters, return target creature to its owner's hand.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

Flash
When Outland Alchemist enters, return another permanent you control to its owner's hand.

Prowess
Foresight — When Outpost Merchant enters, if you've drawn two or more cards this turn, create two 1/1 white Bird creature tokens with flying.

Prowess
Whenever Outsider Alchemist deals combat damage to a player, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Ferocious — When Pack Familiar dies, if you control a creature with power 4 or greater, create two 2/2 green Wolf creature tokens.

Improve {G} ({G}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
When Pack Huntress enters, create a 2/2 green Wolf creature token.

Vigilance
When Paired Pathfinders enters, if three or more colors were spent to cast it, create a 1/1 colorless Servo artifact creature token.

Concord — When Palace Servant enters, if there are four or more card types among permanents you control, create two 1/1 white Merfolk creature tokens.

When Palace Vanguard enters, choose one —
• Create a 1/1 blue Bird creature token with flying.
• Create a 2/2 white Cat creature token.