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 Guardian is an enchantment, Opal Guardian becomes a 3/4 Gargoyle creature with flying and protection from red.

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)

Equipped creature gets +X/+X, where X is the number of charge counters on Opaline Bracers.

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

: Add one mana of any color.

X target creatures can't be blocked this turn. Until end of turn, those creatures gain "Whenever this creature deals combat damage to a player, draw a card."

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

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

Flying

When Opportunistic Dragon enters, choose target Human or artifact an opponent controls. For as long as Opportunistic Dragon remains on the battlefield, gain control of that permanent, it loses all abilities, and it can't attack or block.

Whenever a player casts a spell, that player discards a card.

Counter target spell unless its controller pays for each card in your hand.

Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, put a +1/+1 counter on target creature.

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.

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.

You may play an additional land on each of your turns.

Play with the top card of your library revealed.

You may play lands from the top of your library.

Flying

When Oracle of the Alpha enters the battlefield, conjure the Power Nine into your library, then shuffle.

Whenever Oracle of the Alpha attacks, scry 1.

: All damage that would be dealt to target creature this turn by a source of your choice is dealt to Oracle's Attendants instead.

, : Exile the top card of your library. Until end of turn, you may play that card. Put a brick counter on Oracle's Vault.

: Exile the top card of your library. Until end of turn, you may play that card without paying its mana cost. Activate only if there are three or more brick counters on Oracle's Vault.

Trample

Landfall — Whenever a land you control enters, put a +1/+1 counter on Oran-Rief Hydra. If that land is a Forest, put two +1/+1 counters on Oran-Rief Hydra instead.

When Oran-Rief Ooze enters, put a +1/+1 counter on target creature you control.

Whenever Oran-Rief Ooze attacks, put a +1/+1 counter on each attacking creature with a +1/+1 counter on it.

Whenever Oran-Rief Survivalist or another Ally you control enters, you may put a +1/+1 counter on Oran-Rief Survivalist.

As an additional cost to cast this spell, you may reveal a Dragon card from your hand.

Defender, flying

When Orator of Ojutai enters, if you revealed a Dragon card or controlled a Dragon as you cast this spell, draw a card.

, : Add two mana in any combination of colors. Spend this mana only to cast Dragon spells or activate abilities of Dragons.

, , Sacrifice Orb of Dragonkind: Look at the top seven cards of your library. You may reveal a Dragon card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

: Add one mana of any color.

Other noncreature artifacts are mono and continuous. (Each activated ability of mono artifacts costs an additional to activate if its cost doesn't already include . As long as a continuous artifact is tapped, it loses all abilities.)

Reach (This creature can block creatures with flying.)

Whenever you cast a Spirit or Arcane spell, Orbweaver Kumo gains forestwalk until end of turn. (It can't be blocked as long as defending player controls a Forest.)

Whenever another creature you control enters, target creature an opponent controls gets -1/-1 until end of turn.

Council's dilemma — When Orchard Elemental enters, 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.

When Orchard Strider enters, create two Food tokens. (They're artifacts with ", , Sacrifice this artifact: You gain 3 life.")

Basic landcycling (, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

: Orcish Artillery deals 2 damage to any target and 3 damage to you.

Flash

When Orcish Bowmasters enters and whenever an opponent draws a card except the first one they draw in each of their draw steps, Orcish Bowmasters deals 1 damage to any target. Then amass Orcs 1.

: Orcish Cannoneers deals 2 damage to any target and 3 damage to you.

Orcish Conscripts can't attack unless at least two other creatures attack.

Orcish Conscripts can't block unless at least two other creatures block.

, : Target creature can't be regenerated this turn.

, : Regenerate target black or green creature.

, : Regenerate target black or green creature.

, : Look at the top eight cards of your library. Exile four of them at random, then put the rest on top of your library in any order.

, Sacrifice an artifact: Orcish Mechanics deals 2 damage to any target.

Enchant land

Orcish Mine enters with three ore counters on it.

At the beginning of your upkeep and whenever enchanted land becomes tapped, remove an ore counter from Orcish Mine.

When the last ore counter is removed from Orcish Mine, destroy enchanted land and Orcish Mine deals 2 damage to that land's controller.

When Orcish Paratroopers enters, flip it from a height of at least one foot. Sacrifice Orcish Paratroopers unless it turns over completely at least once during the flip and lands face up.

Trample

Other Orcs and Goblins you control have trample.

Whenever Orcish Siegemaster attacks, it gets +X/+0 until end of turn, where X is the greatest power among creatures you control.

Whenever Orcish Squatters attacks and isn't blocked, you may gain control of target land defending player controls for as long as you control Orcish Squatters. If you do, Orcish Squatters assigns no combat damage this turn.

Orcish Veteran can't block white creatures with power 2 or greater.

: Orcish Veteran gains first strike until end of turn.

Enchant creature

Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice Ordeal of Erebos.

When you sacrifice Ordeal of Erebos, target player discards two cards.

Enchant creature

Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice this Aura.

When you sacrifice this Aura, search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Enchant creature

Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice Ordeal of Thassa.

When you sacrifice Ordeal of Thassa, draw two cards.

Protection from black

: Order of Leitbur gains first strike until end of turn.

: Order of Leitbur gets +1/+0 until end of turn.

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.)

Flying, lifelink, haste

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Other Vampires you control have exalted.

Whenever Order of the Alabaster Host becomes blocked by a creature, that creature gets -1/-1 until end of turn.

Whenever Order of the Golden Cricket attacks, you may pay . If you do, it gains flying until end of turn.