Fecundity

Whenever a creature dies, that creature's controller may draw a card.

Season of Growth

Whenever a creature you control enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Whenever you cast a spell that targets a creature you control, draw a card.

Tasigur's Cruelty

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Each opponent discards two cards.

Stronghold Rats

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Stronghold Rats deals combat damage to a player, each player discards a card.

Leyline of Vitality

If Leyline of Vitality is in your opening hand, you may begin the game with it on the battlefield.
Creatures you control get +0/+1.
Whenever a creature you control enters, you may gain 1 life.

Curse of Predation

Enchant player
Whenever a creature attacks enchanted player, put a +1/+1 counter on it.

Geth's Grimoire

Whenever an opponent discards a card, you may draw a card.

The Eldest Reborn

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each opponent sacrifices a creature or planeswalker of their choice.
II — Each opponent discards a card.
III — Put target creature or planeswalker card from a graveyard onto the battlefield under your control.

Nath of the Gilt-Leaf

At the beginning of your upkeep, you may have target opponent discard a card at random.
Whenever an opponent discards a card, you may create a 1/1 green Elf Warrior creature token.

Sibsig Icebreakers

When Sibsig Icebreakers enters, each player discards a card.

Miasmic Mummy

When Miasmic Mummy enters, each player discards a card.

Hypnotic Specter

Flying
Whenever Hypnotic Specter deals damage to an opponent, that player discards a card at random.

Elvish Doomsayer

When Elvish Doomsayer dies, each opponent discards a card.

Creeping Dread

At the beginning of your upkeep, each player discards a card. Each opponent who discarded a card that shares a card type with the card you discarded loses 3 life. (Players reveal the discarded cards simultaneously.)

Burglar Rat

When this creature enters, each opponent discards a card.

Path of Discovery

Whenever a creature you control enters, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on the creature, then put the card back or put it into your graveyard.)

Abyssal Specter

Flying
Whenever Abyssal Specter deals damage to a player, that player discards a card.

Liliana's Caress

Whenever an opponent discards a card, that player loses 2 life.

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Bottomless Pit

At the beginning of each player's upkeep, that player discards a card at random.

Liliana's Specter

Flying
When Liliana's Specter enters, each opponent discards a card.

Necropolis Regent

Flying
Whenever a creature you control deals combat damage to a player, put that many +1/+1 counters on it.

Gibbering Descent

At the beginning of each player's upkeep, that player loses 1 life and discards a card.
Hellbent — Skip your upkeep step if you have no cards in hand.
Madness {2}{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.)

Rotting Rats

When Rotting Rats enters, each player discards a card.
Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Noxious Vapors

Each player reveals their hand, chooses one card of each color from it, then discards all other nonland cards.

Mindslicer

When Mindslicer dies, each player discards their hand.

Cunning Lethemancer

At the beginning of your upkeep, each player discards a card.

Delirium Skeins

Fraying Omnipotence

Each player loses half their life, then discards half the cards in their hand, then sacrifices half the creatures they control of their choice. Round up each time.

Despair

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Until end of turn, creatures you control gain menace and "Whenever this creature deals combat damage to a player, that player discards a card."

Driven

Until end of turn, creatures you control gain trample and "Whenever this creature deals combat damage to a player, draw a card."

Driven // Despair

Fell Specter

Flying
When Fell Specter enters, target opponent discards a card.
Whenever an opponent discards a card, that player loses 2 life.

Words of Waste

{1}: The next time you would draw a card this turn, each opponent discards a card instead.

Larceny

Whenever a creature you control deals combat damage to a player, that player discards a card.

Sangromancer

Flying
Whenever a creature an opponent controls dies, you may gain 3 life.
Whenever an opponent discards a card, you may gain 3 life.

Dark Deal

Each player discards all the cards in their hand, then draws that many cards minus one.

Guul Draz Specter

Flying
Guul Draz Specter gets +3/+3 as long as an opponent has no cards in hand.
Whenever Guul Draz Specter deals combat damage to a player, that player discards a card.

Honden of Night's Reach

At the beginning of your upkeep, target opponent discards a card for each Shrine you control.

Forbidden Ritual

Sacrifice a nontoken permanent. If you do, target opponent loses 2 life unless that player sacrifices a permanent of their choice or discards a card. You may repeat this process any number of times.

Liliana Vess

+1: Target player discards a card.
−2: Search your library for a card, then shuffle and put that card on top.
−8: Put all creature cards from all graveyards onto the battlefield under your control.

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.

Megrim

Whenever an opponent discards a card, Megrim deals 2 damage to that player.

Moldervine Reclamation

Whenever a creature you control dies, you gain 1 life and draw a card.

Memory Jar

{T}, Sacrifice Memory Jar: Each player exiles all cards from their hand face down and draws seven cards. At the beginning of the next end step, each player discards their hand and returns to their hand each card they exiled this way.

Awaken the Erstwhile

Each player discards all the cards in their hand, then creates that many 2/2 black Zombie creature tokens.

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.