Each non-Vampire creature gets -X/-X until end of turn, where X is the number of Vampires you control.

Each opponent exiles a creature with the greatest power among creatures that player controls.

Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, Olórin's Searing Light deals damage to each opponent equal to the power of the creature they exiled.

When Oltec Archaeologists enters, choose one —

• Return target artifact card from your graveyard to your hand.

• Scry 3. (Look at the top three cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Whenever you cast a creature spell, choose one —

• Create a 1/1 colorless Gnome artifact creature token.

• Create a token that's a copy of target artifact token you control.

Players can't draw cards.

At the beginning of each player's draw step, that player exiles the top card of their library. If it's a land card, the player puts it onto the battlefield. Otherwise, the player casts it without paying its mana cost if able.

Flash

When Omen of the Sea enters, scry 2, then draw a card.

, Sacrifice Omen of the Sea: Scry 2.

Omenport Vigilante has double strike as long as you've committed a crime this turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

, , Sacrifice Ominous Parcel: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.

, , Sacrifice Ominous Parcel: It deals 4 damage to target creature.

When Ominous Traveler enters the battlefield, draft a card from Ominous Traveler's spellbook. That card perpetually gains "You may spend mana as though it were mana of any color to cast this spell" and "When you cast this spell, return a creature named Ominous Traveler you control to its owner's hand."

When Omnath, Locus of Creation enters, draw a card.

Landfall — Whenever a land you control enters, you gain 4 life if this is the first time this ability has resolved this turn. If it's the second time, add . If it's the third time, Omnath deals 4 damage to each opponent and each planeswalker you don't control.

Landfall — Whenever a land you control enters, create a 5/5 red and green Elemental creature token.

Whenever Omnath, Locus of Rage or another Elemental you control dies, Omnath deals 3 damage to any target.

: Target creature becomes a Frog with base power and toughness 3/3 until end of turn.

Whenever Omo, Queen of Vesuva enters or attacks, put an everything counter on each of up to one target land and up to one target creature.

Each land with an everything counter on it is every land type in addition to its other types.

Each nonland creature with an everything counter on it is every creature type.

Enchant creature

Enchanted creature is legendary, gets +1/+1, and has flying, vigilance, and lifelink.

O-Naginata can be attached only to a creature with power 3 or greater.

Equipped creature gets +3/+0 and has trample.

Equip (: Attach to target creature you control. Equip only as a sorcery.)

Creatures can't attack planeswalkers you control unless their controller pays for each creature they control that's attacking a planeswalker you control.

, Exile Onakke Oathkeeper from your graveyard: Return target planeswalker card from your graveyard to the battlefield.

Return target card from your graveyard to your hand. Put up to one other target card from your graveyard on top of your library. Exile Once and Future.

Adamant — If at least three green mana was spent to cast this spell, instead return those cards to your hand and exile Once and Future.

Rally — Whenever Ondu Champion or another Ally you control enters, creatures you control gain trample until end of turn.

First strike

Landfall — Whenever a land you control enters, Ondu Greathorn gets +2/+2 until end of turn.

Whenever an enchantment you control enters, you may create a token that's a copy of it. Do this only once each turn.

Spree (Choose one or more additional costs.)

+ — Return target creature card from your graveyard to the battlefield.

+ — Return target Mount or Vehicle card from your graveyard to the battlefield.

+ — Return target Aura or Equipment card from your graveyard to the battlefield attached to a creature you control.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)

I — The Ring tempts you, then each player mills cards equal to your Ring-bearer's power.

II — Destroy all nonlegendary creatures.

III — Each opponent loses 1 life for each creature card in that player's graveyard.

You lose the game.

Flash

Enchant creature you control

Whenever enchanted creature or another modified creature you control dies, create X 1/1 colorless Spirit creature tokens, where X is that creature's power. (Equipment, Auras you control, and counters are modifications.)

Enchant creature or enchantment

Enchanted permanent is an enchantment and loses all other card types. (It still has its abilities, but it's no longer a creature.)

Defender

Creatures with flying your opponents control get -1/-0.

Whenever one or more creatures you control deal combat damage to a player, investigate. (Create a Clue token. It's an artifact with ", Sacrifice this artifact: Draw a card.")

, Exile a creature card from your graveyard: Investigate. You gain 2 life.

Whenever one or more artifacts you control leave the battlefield during your turn, create a 1/1 colorless Construct artifact creature token. This ability triggers only once each turn.

, Sacrifice an artifact: Oni-Cult Anvil deals 1 damage to each opponent. You gain 1 life.

Target creature gets +X/+0 until end of turn, where X is its power.

Whenever a player casts a black spell, you may pay . If you do, untap target permanent.

Flying

Each other Rogue creature you control enters with an additional +1/+1 counter on it.

Whenever a creature you control with a +1/+1 counter on it deals combat damage to a player, that player discards a card.

Target player draws a card.

Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

, Sacrifice a non-Ooze creature: Create an X/X green Ooze creature token, where X is the sacrificed creature's power. Activate only as a sorcery.

When an opponent casts a creature spell, if Opal Archangel is an enchantment, Opal Archangel becomes a 5/5 Angel creature with flying and vigilance.

When an opponent casts a creature spell, if Opal Caryatid is an enchantment, Opal Caryatid becomes a 2/2 Soldier creature.

When an opponent casts a creature spell, if Opal Gargoyle is an enchantment, Opal Gargoyle becomes a 2/2 Gargoyle creature with flying.

When Opal Lake Gatekeepers enters, if you control two or more Gates, you may draw a card.

When an opponent casts a creature spell, if Opal Titan is an enchantment, Opal Titan becomes a 4/4 Giant creature with protection from each of that spell's colors.

Defender (This creature can't attack.)

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

: The next time a source of your choice would deal damage this turn, that damage is dealt to Opal-Eye, Konda's Yojimbo instead.

: Prevent the next 1 damage that would be dealt to Opal-Eye this turn.

All Slivers have "Whenever this permanent becomes the target of a spell an opponent controls, you may draw a card."

Search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Whenever a nontoken creature you control dies, create a 2/2 black Zombie creature token.

Return all artifact and enchantment cards from all graveyards to the battlefield under their owners' control. (Auras with nothing to enchant remain in graveyards.)

Whenever Ophidian attacks and isn't blocked, you may draw a card. If you do, Ophidian assigns no combat damage this turn.

At the beginning of each upkeep, if you control no Snakes, create a 1/1 black Snake creature token with deathtouch.

Flash

You control your opponents while they're searching their libraries.

While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.

Whenever you crank Optical Optimizer, until end of turn, target creature becomes an artifact in addition to its other types and gains ": Draw a card."

Opulent Palace enters tapped.

: Add , , or .

Haste

Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)

When Oracle of Bones enters, if tribute wasn't paid, you may cast an instant or sorcery spell from your hand without paying its mana cost.