A-Knockout Blow

Knockout Blow

This spell costs {2} less to cast if it targets a red creature.
Knockout Blow deals 4 damage to target attacking or blocking creature and you gain 2 life.

Devil

Maestros Diabolist

Deathtouch, haste
Whenever this creature attacks, if you don't control a Devil token, create a tapped and attacking 1/1 red Devil creature token with "When this token dies, it deals 1 damage to any target."

A-Masked Bandits

Masked Bandits

Vigilance
Menace (This creature can't be blocked except by two or more creatures.)
{2}, Exile this card from your hand: Target land gains "{T}: Add {B}, {R}, or {G}" until this card is cast from exile. You may cast this card for as long as it remains exiled.

Meeting of the Five

Exile the top ten cards of your library. You may cast spells with exactly three colors from among them this turn. Add {W}{W}{U}{U}{B}{B}{R}{R}{G}{G}. Spend this mana only to cast spells with exactly three colors.

A-Metropolis Angel

Metropolis Angel

Flying
Whenever you attack with one or more creatures with counters on them, draw a card.

A-Mr. Orfeo, the Boulder

Mr. Orfeo, the Boulder

Whenever you attack, double target creature's power until end of turn.

Nimble Larcenist

Flying
When this creature enters, target opponent reveals their hand. You choose an artifact, instant, or sorcery card from it and exile that card.

Copy

Ob Nixilis, the Adversary

Casualty X. The copy isn't legendary and has starting loyalty X. (As you cast this spell, you may sacrifice a creature with power X. When you do, copy this spell. The copy becomes a token.)
+1: Each opponent loses 2 life unless they discard a card. If you control a Demon or Devil, you gain 2 life.
−2: Create a 1/1 red Devil creature token with "When this token dies, it deals 1 damage to any target."
−7: Target player draws seven cards and loses 7 life.

Obscura Ascendancy

Spirit

Whenever you cast a spell, if its mana value is equal to 1 plus the number of soul counters on this enchantment, put a soul counter on this enchantment, then create a 2/2 white Spirit creature token with flying.
As long as there are five or more soul counters on this enchantment, Spirits you control get +3/+3.

Obscura Charm

Choose one —
• Return target multicolored permanent card with mana value 3 or less from your graveyard to the battlefield tapped.
• Counter target instant or sorcery spell.
• Destroy target creature or planeswalker with mana value 3 or less.

Obscura Interceptor

Flash
Lifelink
When this creature enters, 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.)

Wizard

Mage's Attendant

When this creature enters, create a 1/1 blue Wizard creature token with "{1}, Sacrifice this token: Counter target noncreature spell unless its controller pays {1}."

Treasure

Ognis, the Dragon's Lash

Haste
Whenever a creature you control with haste attacks, create a tapped Treasure token.

Park Heights Pegasus

Flying, trample
Whenever this creature deals combat damage to a player, draw a card if you had two or more creatures enter the battlefield under your control this turn.

A-Queza, Augur of Agonies

Queza, Augur of Agonies

Whenever you draw a card, target opponent loses 1 life and you gain 1 life.

Raffine, Scheming Seer

Flying, ward {1}
Whenever you attack, target attacking creature connives X, where X is the number of attacking creatures. (Draw X cards, then discard X cards. Put a +1/+1 counter on that creature for each nonland card discarded this way.)

Streets of New Capenna