Rix Maadi Reveler

Spectacle {2}{B}{R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
When Rix Maadi Reveler enters the battlefield, discard a card, then draw a card. If Rix Maadi Reveler's spectacle cost was paid, instead discard your hand, then draw three cards.

Glint-Horn Buccaneer

Haste
Whenever you discard a card, Glint-Horn Buccaneer deals 1 damage to each opponent.
{1}{R}, Discard a card: Draw a card. Activate only if Glint-Horn Buccaneer is attacking.

Neheb, Dreadhorde Champion

Trample
Whenever Neheb, Dreadhorde Champion deals combat damage to a player or planeswalker, you may discard any number of cards. If you do, draw that many cards and add that much {R}. Until end of turn, you don't lose this mana as steps and phases end.

Fiery Temper

Fiery Temper deals 3 damage to any target.
Madness {R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Chainer, Nightmare Adept

Discard a card: You may cast a creature spell from your graveyard this turn. Activate only once each turn.
Whenever a nontoken creature enters the battlefield under your control, if you didn't cast it from your hand, it gains haste until your next turn.

Malfegor

Flying
When Malfegor enters the battlefield, discard your hand. Each opponent sacrifices a creature for each card discarded this way.

Herald of Anguish

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Flying
At the beginning of your end step, each opponent discards a card.
{1}{B}, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.

Reflection of Kiki-Jiki

{1}, {T}: Create a token that's a copy of another target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Fable of the Mirror-Breaker

(As this Saga enters and after your draw step, add a lore counter.)
I — Create a 2/2 red Goblin Shaman creature token with "Whenever this creature attacks, create a Treasure token."
II — You may discard up to two cards. If you do, draw that many cards.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Fable of the Mirror-Breaker // Reflection of Kiki-Jiki

Insolent Neonate

Menace (This creature can't be blocked except by two or more creatures.)
Discard a card, Sacrifice Insolent Neonate: Draw a card.

Archfiend of Ifnir

Flying
Whenever you cycle or discard another card, put a -1/-1 counter on each creature your opponents control.
Cycling {2} ({2}, Discard this card: Draw a card.)

Ghostly Pilferer

Whenever Ghostly Pilferer becomes untapped, you may pay {2}. If you do, draw a card.
Whenever an opponent casts a spell from anywhere other than their hand, draw a card.
Discard a card: Ghostly Pilferer can't be blocked this turn.

Terminal Agony

Destroy target creature.
Madness {B}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Skophos Reaver

As long as it's your turn, Skophos Reaver gets +2/+0.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Lazotep Chancellor

Whenever you discard a card, you may pay {1}. If you do, amass Zombies 2. (Put two +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)

Mishra, Excavation Prodigy

Haste
{1}, {T}, Discard a card: Draw a card.
Whenever you discard one or more artifact cards, add {R}{R}. This ability triggers only once each turn.

Asmoranomardicadaistinaculdacar

As long as you've discarded a card this turn, you may pay {B/R} to cast this spell.
When Asmoranomardicadaistinaculdacar enters the battlefield, you may search your library for a card named The Underworld Cookbook, reveal it, put it into your hand, then shuffle.
Sacrifice two Foods: Target creature deals 6 damage to itself.

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Rakdos Headliner

Haste
Echo—Discard a card. (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

The Underworld Cookbook

{T}, Discard a card: Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
{4}, {T}, Sacrifice The Underworld Cookbook: Return target creature card from your graveyard to your hand.

Zombify

Return target creature card from your graveyard to the battlefield.

Feasting Troll King

Vigilance, trample
When Feasting Troll King enters the battlefield, if you cast it from your hand, create three Food tokens. (They're artifacts with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Sacrifice three Foods: Return Feasting Troll King from your graveyard to the battlefield. Activate only during your turn.

Key to the City

{T}, Discard a card: Up to one target creature can't be blocked this turn.
Whenever Key to the City becomes untapped, you may pay {2}. If you do, draw a card.

Liliana of the Veil

+1: Each player discards a card.
−2: Target player sacrifices a creature.
−6: Separate all permanents target player controls into two piles. That player sacrifices all permanents in the pile of their choice.

Kitchen Imp

Flying, haste
Madness {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.)

Blazing Rootwalla

{R}: Blazing Rootwalla gets +2/+0 until end of turn. Activate only once each turn.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Bone Shards

As an additional cost to cast this spell, sacrifice a creature or discard a card.
Destroy target creature or planeswalker.

Rielle, the Everwise

Rielle, the Everwise gets +1/+0 for each instant and sorcery card in your graveyard.
Whenever you discard one or more cards for the first time each turn, draw that many cards.

Necrogoyf

Necrogoyf's power is equal to the number of creature cards in all graveyards.
At the beginning of each player's upkeep, that player discards a card.
Madness {1}{B}{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.)

Shadow of the Grave

Return to your hand all cards in your graveyard that you cycled or discarded this turn.

Collector's Vault

{2}, {T}: Draw a card, then discard a card. Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Big Score

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")