msem-instigator

Target creature gets -5/-5 until end of turn.
Judge up to one target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

Identity — When Order's Anointer enters, if you control at least two other creatures that share a creature type with it, creatures you control get +1/+1 until end of turn.

Whenever Ore Tunneler deals damage to an opponent, tap target land they control. It doesn't untap during its controller's next untap step.

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

Whenever Organ Scavenger perseveres, each opponent loses 2 life. (A creature perseveres when it survives damage.)

Destroy target artifact or enchantment with mana value 3 or less.
Ferocious — You gain 4 life if you control a creature with power 4 or greater.

Equipped creature gets +1/+1.
Whenever equipped creature deals combat damage to a player, Ornamental Longbow deals 1 damage to any target.
Equip {2}

{1}, Sacrifice Ornate Incense: Draw a card. You gain 1 life.

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

When Ornery Bull enters, return a creature you control to its owner's hand.

Defender
Whenever another creature you control enters, Orphan of the Nav gets +1/+1 until end of turn and can attack as though it didn't have defender this turn.

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.)

Lifelink
At the beginning of your upkeep, Osgaerith Desecrator deals 1 damage to up to one target creature.

Deception {B} ({B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When Oshiruko Operative enters, target player loses 1 life.

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.

Oshiruko Whisperwalker can't be blocked except by Rogues.
Whenever a creature is returned to its owner's hand, you may draw a card. If you do, discard a card.

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

When Osseous Augur enters, target creature an opponent controls gets -1/-1 until end of turn. If that creature's controller is cursed, that creature gets -3/-3 until end of turn instead.

({T}: Add {G}.)
Wanderlust — Otherworldly Forest enters tapped unless you control four or more other differently named lands.
{1}, {T}: Add one mana of any color.

Reveal the top four cards of your library. You may put a creature or land card from among them into your hand. Put the rest into your graveyard.

({T}: Add {U}.)
Wanderlust — Otherworldly Island enters tapped unless you control four or more other differently named lands.
{1}, {T}: Add one mana of any color.

({T}: Add {R}.)
Wanderlust — Otherworldly Mountain enters tapped unless you control four or more other differently named lands.
{1}, {T}: Add one mana of any color.

({T}: Add {W}.)
Wanderlust — Otherworldly Plains enters tapped unless you control four or more other differently named lands.
{1}, {T}: Add one mana of any color.

({T}: Add {B}.)
Wanderlust — Otherworldly Swamp enters tapped unless you control four or more other differently named lands.
{1}, {T}: Add one mana of any color.

Manifest the top card of your library and the bottom card of your library. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)