Hero's Downfall

Caverns of Despair

No more than two creatures can attack each combat.
No more than two creatures can block each combat.

Dismal Failure

Counter target spell. Its controller discards a card.

Agonizing Memories

Look at target player's hand and choose two cards from it. Put them on top of that player's library in any order.

Vraska's Fall

Each opponent sacrifices a creature or planeswalker of their choice and gets a poison counter.

Tragic Lesson

Draw two cards. Then discard a card unless you return a land you control to its owner's hand.

Emissary of Despair

Flying
Whenever Emissary of Despair deals combat damage to a player, that player loses 1 life for each artifact they control.

Divide by Zero

Return target spell or permanent with mana value 1 or greater to its owner's hand.
Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Languish

All creatures get -4/-4 until end of turn.

Die Young

Choose target creature. You get {E}{E} (two energy counters), then you may pay any amount of {E}. The creature gets -1/-1 until end of turn for each {E} paid this way.

Kess, Dissident Mage

Flying
Once during each of your turns, you may cast an instant or sorcery spell from your graveyard. If a spell cast this way would be put into your graveyard, exile it instead.

Abandon Hope

As an additional cost to cast this spell, discard X cards.
Look at target opponent's hand and choose X cards from it. That player discards those cards.

Drown in Sorrow

All creatures get -2/-2 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Rottenheart Ghoul

When Rottenheart Ghoul dies, target player discards a card.

Feldon of the Third Path

{2}{R}, {T}: Create a token that's a copy of target creature card in your graveyard, except it's an artifact in addition to its other types. It gains haste. Sacrifice it at the beginning of the next end step.

Nuclear Fallout

Each creature gets twice -X/-X until end of turn. Each player gets X rad counters.

Beast of Burden

Beast of Burden's power and toughness are each equal to the number of creatures on the battlefield.

Anger of the Gods

Anger of the Gods deals 3 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

Jilt

Kicker {1}{R} (You may pay an additional {1}{R} as you cast this spell.)
Return target creature to its owner's hand. If this spell was kicked, it deals 2 damage to another target creature.

Paranoid Delusions

Target player mills three cards.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Archfiend of Despair

Flying
Your opponents can't gain life.
At the beginning of each end step, each opponent loses life equal to the life that player lost this turn. (Damage causes loss of life.)

Tragic Fall

Target creature gets -3/-3 until end of turn.
Hellbent — That creature gets -13/-13 until end of turn instead if you have no cards in hand.

Wandering Ones

Melancholy

Enchant creature
When Melancholy enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.
At the beginning of your upkeep, sacrifice Melancholy unless you pay {B}.

Recover

Return target creature card from your graveyard to your hand.
Draw a card.

Soul Feast

Target player loses 4 life and you gain 4 life.

Agonizing Remorse

Target opponent reveals their hand. You choose a nonland card from it or a card from their graveyard. Exile that card. You lose 1 life.

Invoke Despair

Target opponent sacrifices a creature of their choice. If they can't, they lose 2 life and you draw a card. Then repeat this process for an enchantment and a planeswalker.

Bereavement

Whenever a green creature dies, its controller discards a card.

Night of Souls' Betrayal

Cecily, Haunted Mage

Your maximum hand size is eleven.
Whenever Cecily, Haunted Mage attacks, you draw a card and you lose 1 life. Then if you have eleven or more cards in your hand, you may cast an instant or sorcery spell from your hand without paying its mana cost.
Friends forever (You can have two commanders if both have friends forever.)

Tendrils of Despair

As an additional cost to cast this spell, sacrifice a creature.
Target opponent discards two cards.

Unfulfilled Desires

{1}, Pay 1 life: Draw a card, then discard a card.

Misguided Rage

Target player sacrifices a permanent of their choice.

Aether Snap

Remove all counters from all permanents and exile all tokens.

Urza's Guilt

Each player draws two cards, then discards three cards, then loses 4 life.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Live Fast

You draw two cards, lose 2 life, and get {E}{E} (two energy counters).

Induce Despair

As an additional cost to cast this spell, reveal a creature card from your hand.
Target creature gets -X/-X until end of turn, where X is the revealed card's mana value.

Solemn Simulacrum

When Solemn Simulacrum enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When Solemn Simulacrum dies, you may draw a card.

Whispering Madness

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Castaway's Despair

Enchant creature
When Castaway's Despair enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Shadow of Doubt

({U/B} can be paid with either {U} or {B}.)
Players can't search libraries this turn.
Draw a card.

Carnival of Souls

Whenever a creature enters, you lose 1 life and add {B}.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

To the Slaughter

Target player sacrifices a creature or planeswalker of their choice.
Delirium — If there are four or more card types among cards in your graveyard, instead that player sacrifices a creature and a planeswalker of their choice.