Whenever Odious Witch attacks, defending player loses 1 life and you gain 1 life.

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Whenever Odylic Wraith deals damage to a player, that player discards a card.

Counter target spell unless its controller pays . You gain 4 life.

Menace

Whenever Ogre Chitterlord enters the battlefield or attacks, create two 1/1 black Rat creature tokens with "This creature can't block." Then if you control five or more Rats, each Rat you control gets +2/+0 until end of turn.

, Discard a card at random: Ogre Shaman deals 2 damage to any target.

Reach

Untap all Archers you control during each other player's untap step.

Whenever an Archer you control deals damage to a creature, you may pay . If you do, draw a card.

Whenever Ohran Viper deals combat damage to a creature, destroy that creature at end of combat.

Whenever Ohran Viper deals combat damage to a player, you may draw a card.

Trample

If a red source you control would deal an amount of noncombat damage less than Ojer Axonil's power to an opponent, that source deals damage equal to Ojer Axonil's power instead.

When Ojer Axonil dies, return it to the battlefield tapped and transformed under its owner's control.

Flying

Whenever you cast an instant spell from your hand, it gains rebound. (Exile it as it resolves. At the beginning of your next upkeep, you may cast it from exile without paying its mana cost.)

When Ojer Pakpatiq dies, return it to the battlefield tapped and transformed under its owner's control with three time counters on it.

Tap target creature. It doesn't untap during its controller's next untap step.

Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Flying, trample

Whenever O-Kagachi, Vengeful Kami deals combat damage to a player, if that player attacked you during their last turn, exile target nonland permanent that player controls.

Double strike, indestructible

Oketra the True can't attack or block unless you control at least three other creatures.

: Create a 1/1 white Warrior creature token with vigilance.

As long as you have more cards in hand than each opponent, Okina Nightwatch gets +3/+3.

At the beginning of combat on your turn, Oko, the Ringleader becomes a copy of up to one target creature you control until end of turn, except he has hexproof.

+1: Draw two cards. If you've committed a crime this turn, discard a card. Otherwise, discard two cards.

−1: Create a 3/3 green Elk creature token.

−5: For each other nonland permanent you control, create a token that's a copy of that permanent.

+2: Create a Food token. (It's an artifact with ", , Sacrifice this artifact: You gain 3 life.")

+1: Target artifact or creature loses all abilities and becomes a green Elk creature with base power and toughness 3/3.

−5: Exchange control of target artifact or creature you control and target creature an opponent controls with power 3 or less.

As this creature transforms into Olag, Ludevic's Hubris, it becomes a copy of a creature card exiled with it, except its name is Olag, Ludevic's Hubris, it's 4/4, and it's a legendary blue and black Zombie in addition to its other colors and types. Put a number of +1/+1 counters on Olag equal to the number of creature cards exiled with it.

You may choose not to untap Old Man of the Sea during your untap step.

: Gain control of target creature with power less than or equal to Old Man of the Sea's power for as long as Old Man of the Sea remains tapped and that creature's power remains less than or equal to Old Man of the Sea's power.

When Old-Growth Dryads enters the battlefield, each opponent may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.

Trample

When Old-Growth Troll dies, if it was a creature, return it to the battlefield. It's an Aura enchantment with enchant Forest you control and "Enchanted Forest has ‘: Add ' and ‘, , Sacrifice this land: Create a tapped 4/4 green Troll Warrior creature token with trample.'"

Target creature gets -2/-2 until end of turn. If it's night, that creature gets -13/-13 until end of turn instead.

Trample

Olog-hai Crusher can't block unless you control a Goblin or Orc.

When Oltec Archaeologists enters the battlefield, 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.)

: Add . Spend this mana only to activate abilities.

Flash

When Omen of the Dead enters the battlefield, return target creature card from your graveyard to your hand.

, Sacrifice Omen of the Dead: Scry 2.

Flash

When Omen of the Hunt enters the battlefield, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

, Sacrifice Omen of the Hunt: Scry 2.

Flash

When Omen of the Sun enters the battlefield, create two 1/1 white Human Soldier creature tokens and you gain 2 life.

, Sacrifice Omen of the Sun: Scry 2.

Flying

Whenever you cycle or discard a card, target creature an opponent controls gets -2/-0 until end of turn.

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

Landfall — Whenever a land enters the battlefield under your control, 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 enters the battlefield under your control, 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.

Creatures you control get +2/+1 until end of turn. Investigate. (Create a Clue token. It's an artifact with ", Sacrifice this artifact: Draw a card.")

Enchant snow land you control

When On Thin Ice enters the battlefield, exile target creature an opponent controls until On Thin Ice leaves the battlefield.

Exile all permanents and all cards from all graveyards. Each player shuffles their hand into their library, then draws seven cards. Each player's life total becomes 10. Exile Once More with Feeling.

DCI ruling — A deck can have only one card named Once More with Feeling.

First strike

Landfall — Whenever a land enters the battlefield under your control, Ondu Greathorn gets +2/+2 until end of turn.

At the beginning of each upkeep, if a player cast two or more spells last turn, transform One of the Pack.

Enchant creature

Enchanted creature can't attack or block, and its activated abilities can't be activated.

At the beginning of the upkeep of enchanted creature's controller, that player loses 1 life.

Enchant creature

Whenever enchanted creature deals combat damage to a player, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

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.)

You may look at the top card of your library any time.

You may play lands and cast spells from the top of your library.

Once during each of your turns, you may cast a spell from your hand or the top of your library without paying its mana cost.

Enchant creature

Enchanted creature gets +2/+2 and has flying.

Whenever you cast a creature spell, tap target creature.

Whenever an opponent casts a creature spell, if Opal Acrolith is an enchantment, Opal Acrolith becomes a 2/4 Soldier creature.

: Opal Acrolith becomes an enchantment.

When an opponent casts a creature spell, if Opal Champion is an enchantment, Opal Champion becomes a 3/3 Knight creature with first strike.

Search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Choose one —

• Add two mana of any one color and two mana of any other color. Spend this mana only to cast creature or enchantment spells.

• Creatures you control get +1/+0 until end of turn.

X can't be greater than the number of players in the game.

Reveal cards from the top of your library until you reveal X land cards. Put those land cards onto the battlefield tapped and the rest on the bottom of your library in a random order.

Flash (You may cast this spell any time you could cast an instant.)

Enchant creature

Whenever enchanted creature deals damage to an opponent, you may draw a card.

More Than Meets the Eye (You may cast this card converted for .)

At the beginning of each end step, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

When Optimus Prime dies, return it to the battlefield converted under its owner's control.

Lifelink

Whenever Orah, Skyclave Hierophant or another Cleric you control dies, return target Cleric card with lesser mana value from your graveyard to the battlefield.

Oran-Rief, the Vastwood enters the battlefield tapped.

: Add .

: Put a +1/+1 counter on each green creature that entered the battlefield this turn.

Council's dilemma — When Orchard Elemental enters the battlefield, starting with you, each player votes for sprout or harvest. Put two +1/+1 counters on Orchard Elemental for each sprout vote. You gain 3 life for each harvest vote.