Desperate Bloodseeker

Lifelink
When Desperate Bloodseeker enters the battlefield, target player mills two cards. (They put the top two cards of their library into their graveyard.)

Halo-Charged Skaab

When Halo-Charged Skaab enters the battlefield, each player mills two cards. Then you may put an instant, sorcery, or battle card from your graveyard on top of your library. (To mill two cards, a player puts the top two cards of their library into their graveyard.)

One Ring to Rule Them All

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — The Ring tempts you, then each player mills cards equal to your Ring-bearer's power.
II — Destroy all nonlegendary creatures.
III — Each opponent loses 1 life for each creature card in that player's graveyard.

Raul, Trouble Shooter

Once during each of your turns, you may cast a spell from among cards in your graveyard that were milled this turn.
{T}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Eye Collector

Flying
Whenever Eye Collector deals combat damage to a player, each player mills a card.

Cut Your Losses

Casualty 2 (As you cast this spell, you may sacrifice a creature with power 2 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Target player mills half their library, rounded down.

Terisian Mindbreaker

Whenever Terisian Mindbreaker attacks, defending player mills half their library, rounded up.
Unearth {1}{U}{U}{U} ({1}{U}{U}{U}: 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.)

Returned Reveler

When Returned Reveler dies, each player mills three cards.

Extract from Darkness

Each player mills two cards. Then you put a creature card from a graveyard onto the battlefield under your control.

King Narfi's Betrayal

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each player mills four cards. Then you may exile a creature or planeswalker card from each graveyard.
II, III — Until end of turn, you may cast spells from among cards exiled with King Narfi's Betrayal, and you may spend mana as though it were mana of any color to cast those spells.

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Tenured Oilcaster

Menace (This creature can't be blocked except by two or more creatures.)
Tenured Oilcaster gets +3/+0 as long as an opponent has eight or more cards in their graveyard.
Whenever Tenured Oilcaster attacks or blocks, each player mills a card.

Whetstone

Stitcher Geralf

{2}{U}, {T}: Each player mills three cards. Exile up to two creature cards put into graveyards this way. Create an X/X blue Zombie creature token, where X is the total power of the cards exiled this way.

Fascination

Choose one —
• Each player draws X cards.
• Each player mills X cards.

Flitting Guerrilla

Flying
When Flitting Guerrilla dies, each player mills two cards. Then you may exile Flitting Guerrilla. When you do, put target creature or battle card from your graveyard on top of your library. (To mill two cards, a player puts the top two cards of their library into their graveyard.)

Chill of Foreboding

Each player mills five cards.
Flashback {7}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Mindwrack Harpy

Flying
At the beginning of combat on your turn, each player mills three cards.

Maddening Cacophony

Kicker {3}{U}
Each opponent mills eight cards. If this spell was kicked, instead each opponent mills half their library, rounded up.

Ghoulcaller's Bell

Breach the Multiverse

Each player mills ten cards. For each player, choose a creature or planeswalker card in that player's graveyard. Put those cards onto the battlefield under your control. Then each creature you control becomes a Phyrexian in addition to its other types.

Duskmantle, House of Shadow

{T}: Add {C}.
{U}{B}, {T}: Target player mills a card.

Drownyard Amalgam

When Drownyard Amalgam enters the battlefield, target player mills three cards. (They put the top three cards of their library into their graveyard.)
{2}{U}: Drownyard Amalgam can't be blocked this turn.

Lazotep Convert

You may have Lazotep Convert enter the battlefield as a copy of any creature card in a graveyard, except it's a 4/4 black Zombie in addition to its other colors and types.

Invasion of Amonkhet

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Amonkhet enters the battlefield, each player mills three cards, then each opponent discards a card and you draw a card. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Invasion of Amonkhet // Lazotep Convert

Bond of Insight

Each player mills four cards. Return up to two instant and/or sorcery cards from your graveyard to your hand. Exile Bond of Insight.

Ashiok, Sculptor of Fears

+2: Draw a card. Each player mills two cards.
−5: Put target creature card from a graveyard onto the battlefield under your control.
−11: Gain control of all creatures target opponent controls.

Shared Trauma

Join forces — Starting with you, each player may pay any amount of mana. Each player mills X cards, where X is the total amount of mana paid this way.

Traumatize

Target player mills half their library, rounded down.

Koma's Faithful

Lifelink
When Koma's Faithful dies, each player mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Winds of Rebuke

Return target nonland permanent to its owner's hand. Each player mills two cards.

Disturbing Conversion

Flash
Enchant creature
When Disturbing Conversion enters the battlefield, each player mills two cards.
Enchanted creature gets -X/-0, where X is the number of cards in its controller's graveyard.

Unseal the Necropolis

Each player mills three cards. Then you return up to two creature cards from your graveyard to your hand. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Can't Wake Up

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Cruel Somnophage

Cruel Somnophage's power and toughness are each equal to the number of creature cards in all graveyards.

Cruel Somnophage // Can't Wake Up

Vantress Gargoyle

Flying
Vantress Gargoyle can't attack unless defending player has seven or more cards in their graveyard.
Vantress Gargoyle can't block unless you have four or more cards in hand.
{T}: Each player mills a card.

Dread Summons

Each player mills X cards. For each creature card put into a graveyard this way, you create a tapped 2/2 black Zombie creature token.

Atrocious Experiment

Target player mills two cards, draws two cards, and loses 2 life. (To mill a card, a player puts the top card of their library into their graveyard.)

Shadow Kin

Flash
At the beginning of your upkeep, each player mills three cards. You may exile a creature card from among the cards milled this way. If you do, Shadow Kin becomes a copy of that card, except it has this ability.