Wound Reflection

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Obosh, the Preypiercer

Companion — Your starting deck contains only cards with odd mana values and land cards. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
If a source you control with an odd mana value would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Zagras, Thief of Heartbeats

This spell costs {1} less to cast for each creature in your party.
Flying, deathtouch, haste
Other creatures you control have deathtouch.
Whenever a creature you control deals combat damage to a planeswalker, destroy that planeswalker.

Agent of Erebos

Constellation — Whenever this creature or another enchantment you control enters, exile target player's graveyard.

Sneak Attack

{R}: You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice the creature at the beginning of the next end step.

Rain of Gore

If a spell or ability would cause its controller to gain life, that player loses that much life instead.

Marchesa's Decree

When this enchantment enters, you become the monarch.
Whenever a creature attacks you or a planeswalker you control, that creature's controller loses 1 life.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Mirage Mirror

{2}: This artifact becomes a copy of target artifact, creature, enchantment, or land until end of turn.

Commune with Lava

Exile the top X cards of your library. Until the end of your next turn, you may play those cards.

War's Toll

Whenever an opponent taps a land for mana, tap all lands that player controls.
If a creature an opponent controls attacks, all creatures that opponent controls attack if able.

Price of Glory

Whenever a player taps a land for mana, if it's not that player's turn, destroy that land.

Curse of Opulence

Enchant player
Whenever enchanted player is attacked, create a Gold token. Each opponent attacking that player does the same. (A Gold token is an artifact with "Sacrifice this token: Add one mana of any color.")

Dictate of the Twin Gods

Flash
If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Stolen Strategy

At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.

Rakdos Charm

Choose one —
• Exile target player's graveyard.
• Destroy target artifact.
• Each creature deals 1 damage to its controller.

Forgeborn Oreads

Constellation — Whenever this creature or another enchantment you control enters, this creature deals 1 damage to any target.

Mogis, God of Slaughter

Indestructible
As long as your devotion to black and red is less than seven, Mogis isn't a creature.
At the beginning of each opponent's upkeep, Mogis deals 2 damage to that player unless they sacrifice a creature of their choice.

Void

Choose a number. Destroy all artifacts and creatures with mana value equal to that number. Then target player reveals their hand and discards all nonland cards with mana value equal to the number.

Chandra's Ignition

Target creature you control deals damage equal to its power to each other creature and each opponent.

Fervor

Creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Polluted Bonds

Whenever a land an opponent controls enters, that player loses 2 life and you gain 2 life.

Curse of Fool's Wisdom

Enchant player
Whenever enchanted player draws a card, they lose 2 life and you gain 2 life.
Madness {3}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Kolaghan's Command

Choose two —
• Return target creature card from your graveyard to your hand.
• Target player discards a card.
• Destroy target artifact.
• Kolaghan's Command deals 2 damage to any target.

Fiery Emancipation

If a source you control would deal damage to a permanent or player, it deals triple that damage to that permanent or player instead.

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.