msem-instigator

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

Vigilance
You may look at the top card of your library any time.
Whenever you cast a creature spell from your hand, you may cast the top card of your library without paying its mana cost if it's a creature card with lesser mana value.

At the beginning of your upkeep, scry 1, then you gain 1 life.

Flying, vigilance
Orzhov Benefactor can't attack or block unless you pay {1} for each debt counter on it.
At the beginning of your upkeep, put a debt counter on Orzhov Benefactor.
{2}: Remove a debt counter from Orzhov Benefactor.

Whenever you make first contact, Oscuran Wingmate gains flying until end of turn. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Exile target nontoken permanent you control, then return that card to the battlefield under its owner's control.

When Oshiruko Purifier enters, create a 2/2 colorless Spirit creature token.
Colorless creatures you control have lifelink.

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

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Oslyd Heretic gets +1/+1 as long as you control no other creatures.

When Ostracizer Orb enters, exile target nonartifact, nonland permanent until Ostracizer Orb leaves the battlefield.

Create X 1/1 blue Elemental creature tokens with flying.
Augmented — If you've spent {W}{U}{B}{R}{G} to cast spells this turn, creatures you control gain haste and vigilance until end of turn.

Exile any number of target creatures you control. At the beginning of the next end step, return to the battlefield tapped each creature card exiled this way and each creature card put into your graveyard from the battlefield this turn.

Enchant player
At the beginning of enchanted player's upkeep, they tap an untapped creature they control.

Exile target creature. That creature's controller creates a 1/1 blue Elemental creature token with flying.

{1}{W}, Exile Outcast of the Folded Fan from your graveyard: Create a 1/1 white Bird creature token with flying. Activate only as a sorcery.

Outer Wall Guard enters with a +1/+1 counter on it if you gained life this turn.

Destroy target attacking or blocking creature.

Vigilance, lifelink

Lifelink
Outskirts Provider enters with a +1/+1 counter on it if a creature attacked this turn and wasn't blocked.

Destroy target creature with power 4 or greater. (You need a target to cast this spell.)
Tap up to two target creatures.

When Overconfident Batter dies, if it's enchanted or you cast a spell that targeted it this turn, you gain 3 life.

Until end of turn, creatures you control have base power X/Y, where X is the greatest base power among creatures you control and Y is the greatest base toughness among creatures you control.
If you control a creature with flying, creatures you control gain flying until end of turn. The same is true for first strike, haste, lifelink, menace, prowess, trample, and vigilance.

When Overgrowth Guardian enters, germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Enchant creature
Enchanted creature can't attack or block.

Enchant creature
Prevent all damage that would be dealt by enchanted creature.