When Nurturing Bristleback enters the battlefield, create a 3/3 green Dinosaur creature token.

Forestcycling (, Discard this card: Search your library for a Forest card, reveal it, put it into your hand, then shuffle.)

Whenever you gain life, you may put that many +1/+1 counters on each creature you control. Do this only once each turn.

Constellation — Whenever Nylea's Colossus or another enchantment enters the battlefield under your control, double target creature's power and toughness until end of turn.

Bestow (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)

Trample

Enchanted creature gets +3/+3 and has trample.

When Nylea's Huntmaster enters the battlefield, target creature you control gets +X/+0 until end of turn, where X is your devotion to green. (Each in the mana costs of permanents you control counts toward your devotion to green.)

Enchant land

When Nylea's Presence enters the battlefield, draw a card.

Enchanted land is every basic land type in addition to its other types.

You have no maximum hand size.

Sonic Booster — Whenever Nyssa of Traken attacks, sacrifice X artifacts. When you sacrifice one or more artifacts this way, tap up to X target creatures and you draw X cards.

Doctor's companion (You can have two commanders if the other is the Doctor.)

Nyx Lotus enters the battlefield tapped.

: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Bestow (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)

Enchanted creature gets +1/+2.

Whenever you crank Oaken Power Suit, target creature gets +X/+X until end of turn, where X is the greatest power among creatures you control.

This spell costs less to cast if an opponent controls a green permanent.

Deathtouch

Whenever Oakhame Adversary deals combat damage to a player, draw a card.

You may cast Oakshade Stalker as though it had flash if you pay more to cast it.

Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

: Prevent the next 1 damage that would be dealt to target creature this turn.

: Add one mana of any color.

, Exert Oasis Ritualist: Add two mana of any one color. (An exerted creature won't untap during your next untap step.)

At the beginning of each player's upkeep, that player chooses target player whose graveyard has fewer creature cards in it than their graveyard does and is their opponent. The first player may return a creature card from their graveyard to their hand.

At the beginning of each player's upkeep, that player chooses target player who has more life than they do and is their opponent. The first player may have Oath of Mages deal 1 damage to the second player.

At the beginning of each player's upkeep, that player chooses target player who has more cards in hand than they do and is their opponent. The first player may discard their hand and draw three cards.

Equipped creature gets +3/+1.

Whenever equipped creature dies, return that card to the battlefield under your control if it's a Samurai card.

When Oathkeeper, Takeno's Daisho is put into a graveyard from the battlefield, exile equipped creature.

Equip

Oathsworn Knight enters the battlefield with four +1/+1 counters on it.

Oathsworn Knight attacks each combat if able.

If damage would be dealt to Oathsworn Knight while it has a +1/+1 counter on it, prevent that damage and remove a +1/+1 counter from it.

+2: Each opponent loses 1 life. You gain life equal to the life lost this way.

−2: Create a 5/5 black Demon creature token with flying. You lose 2 life.

−8: You get an emblem with ", Sacrifice a creature: You gain X life and draw X cards, where X is the sacrificed creature's power."

Ob Nixilis of the Black Oath can be your commander.

Flying, trample

Whenever one or more opponents each lose exactly 1 life, put a +1/+1 counter on Ob Nixilis, Captive Kingpin. Exile the top card of your library. Until your next end step, you may play that card.

Landfall — Whenever a land enters the battlefield under your control, you may have target player lose 3 life. If you do, put three +1/+1 counters on Ob Nixilis, the Fallen.

Flying, trample

Whenever an opponent searches their library, that player sacrifices a creature and loses 10 life.

Whenever another creature dies, put a +1/+1 counter on Ob Nixilis, Unshackled.

: The player whose turn it is may end the turn. (Exile all spells and abilities from the stack. The player whose turn it is discards down to their maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

, : You gain 5 life.

, : Draw a card, then discard a card.

, : Target creature gets -2/-2 until end of turn.

, : Obelisk of Alara deals 3 damage to target player or planeswalker.

, : Target creature gets +4/+4 until end of turn.

: Add , , or .

: Add , , or .

, : Return target permanent you both own and control to your hand.

Reach

Whenever Obelisk Spider deals combat damage to a creature, put a -1/-1 counter on that creature.

Whenever you put one or more -1/-1 counters on a creature, each opponent loses 1 life and you gain 1 life.

When you cast this spell, target opponent exiles the top four cards of their library, then you may put any number of land cards that player owns from exile onto the battlefield under your control.

Devoid (This card has no color.)

Exile target creature.

: Add .

: Return Oboro, Palace in the Clouds to its owner's hand.

Whenever you cast a spell, if its mana value is equal to 1 plus the number of soul counters on Obscura Ascendancy, put a soul counter on Obscura Ascendancy, then create a 2/2 white Spirit creature token with flying.

As long as there are five or more soul counters on Obscura Ascendancy, Spirits you control get +3/+3.

Choose three. You may choose the same mode more than once.

• Until end of turn, target creature loses all abilities and has base power and toughness 1/1.

• Target creature connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)

• Target player returns a creature card from their graveyard to their hand.

Flash

Lifelink

When Obscura Interceptor enters the battlefield, it connives. When it connives this way, return up to one target spell to its owner's hand. (To have a creature connive, draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)

When Obscura Storefront enters the battlefield, sacrifice it. When you do, search your library for a basic Plains, Island, or Swamp card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

If you control a commander, you may cast this spell without paying its mana cost.

Prevent all damage that would be dealt this turn by creatures your opponents control.

If it's neither day nor night, it becomes day as Obsessive Astronomer enters the battlefield.

Whenever day becomes night or night becomes day, discard up to two cards, then draw that many cards.

Draw a card.

Madness (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

: Draw a card, then discard a card.

, , Sacrifice Obsessive Stitcher: Return target creature card from your graveyard to the battlefield.

Protection from black

: Target creature gains protection from black until end of turn.

This spell costs less to cast for each land your opponents control that could produce .

Flying

When Obsidian Charmaw enters the battlefield, destroy target nonbasic land an opponent controls.

When Obstinate Baloth enters the battlefield, you gain 4 life.

If a spell or ability an opponent controls causes you to discard Obstinate Baloth, put it onto the battlefield instead of putting it into your graveyard.

At the beginning of combat on your turn, up to one target land you control becomes an X/X Elemental creature with trample and haste until end of turn, where X is Obuun's power. It's still a land.

Landfall — Whenever a land enters the battlefield under your control, put a +1/+1 counter on target creature.

Flying

Return target permanent card from your graveyard to the battlefield.

Deathtouch

All creatures able to block Ochran Assassin do so.

When Octo Opus enters the battlefield, create a 4/4 blue Octopus Performer creature token named Contortionist with "At the beginning of your upkeep, you may fold this token in half." (It becomes 2/2, then 1/1, ½/½, and so on.)

Sacrifice Octo Opus: Draw a card and an additional card for each of Contortionist's folds.