Maybe

Helm of Awakening

Have

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

Rest in Peace

When Rest in Peace enters the battlefield, exile all graveyards.
If a card or token would be put into a graveyard from anywhere, exile it instead.

Drowned Secrets

Whenever you cast a blue spell, target player mills two cards.

Jace's Scrutiny

Target creature gets -4/-0 until end of turn.
Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Real maybe!

Winds of Rebuke

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

Kwain, Itinerant Meddler

{T}: Each player may draw a card, then each player who drew a card this way gains 1 life.

Field Research

Kicker {2}{U} (You may pay an additional {2}{U} as you cast this spell.)
Draw two cards. If this spell was kicked, draw three cards instead.

Cathar Commando

Flash
{1}, Sacrifice Cathar Commando: Destroy target artifact or enchantment.

Glasspool Shore

Glasspool Shore enters the battlefield tapped.
{T}: Add {U}.

Glasspool Mimic

You may have Glasspool Mimic enter the battlefield as a copy of a creature you control, except it's a Shapeshifter Rogue in addition to its other types.

Glasspool Mimic // Glasspool Shore

Benevolent Geist

Flying
Noncreature spells you control can't be countered.
If Benevolent Geist would be put into a graveyard from anywhere, exile it instead.

Malevolent Hermit

{U}, Sacrifice Malevolent Hermit: Counter target noncreature spell unless its controller pays {3}.
Disturb {2}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Malevolent Hermit // Benevolent Geist

Skybridge Towers

Skybridge Towers enters the battlefield tapped.
{T}: Add {W} or {U}.
{2}{W}{U}, {T}, Sacrifice Skybridge Towers: Draw a card.

Sphinx's Revelation

Shimmer Dragon

Flying
As long as you control four or more artifacts, Shimmer Dragon has hexproof.
Tap two untapped artifacts you control: Draw a card.

Sphinx's Tutelage

Whenever you draw a card, target opponent mills two cards. If two nonland cards that share a color were milled this way, repeat this process.
{5}{U}: Draw a card, then discard a card.

Starnheim Courser

Flying
Artifact and enchantment spells you cast cost {1} less to cast.

Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Patrician Geist

Flying
Other Spirits you control get +1/+1.
Spells you cast from your graveyard cost {1} less to cast.

Psychic Corrosion

Whenever you draw a card, each opponent mills two cards.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Brokers Hideout

When Brokers Hideout enters the battlefield, sacrifice it. When you do, search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Solemn Simulacrum

When Solemn Simulacrum enters the battlefield, 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.

Emry, Lurker of the Loch

This spell costs {1} less to cast for each artifact you control.
When Emry, Lurker of the Loch enters the battlefield, mill four cards.
{T}: Choose target artifact card in your graveyard. You may cast that card this turn. (You still pay its costs. Timing rules still apply.)

Tasha's Hideous Laughter

Each opponent exiles cards from the top of their library until that player has exiled cards with total mana value 20 or more.

Fractured Sanity

Each opponent mills fourteen cards.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)
When you cycle Fractured Sanity, each opponent mills four cards.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Font of Mythos

At the beginning of each player's draw step, that player draws two additional cards.

Manic Scribe

When Manic Scribe enters the battlefield, each opponent mills three cards.
Delirium — At the beginning of each opponent's upkeep, if there are four or more card types among cards in your graveyard, that player mills three cards.

Pit of Offerings

Pit of Offerings enters the battlefield tapped.
When Pit of Offerings enters the battlefield, exile up to three target cards from graveyards.
{T}: Add {C}.
{T}: Add one mana of any of the exiled cards' colors.

Plains

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Stonespeaker Crystal: Exile any number of target players' graveyards. Draw a card.

Archaeomancer

When Archaeomancer enters the battlefield, return target instant or sorcery card from your graveyard to your hand.

Teferi's Tutelage

When Teferi's Tutelage enters the battlefield, draw a card, then discard a card.
Whenever you draw a card, target opponent mills two cards. (They put the top two cards of their library into their graveyard.)

Midnight Clock

{T}: Add {U}.
{2}{U}: Put an hour counter on Midnight Clock.
At the beginning of each upkeep, put an hour counter on Midnight Clock.
When the twelfth hour counter is put on Midnight Clock, shuffle your hand and graveyard into your library, then draw seven cards. Exile Midnight Clock.

Arcane Melee

Instant and sorcery spells cost {2} less to cast.

Supreme Verdict

This spell can't be countered.
Destroy all creatures.

Millstone

Visions of Beyond

Draw a card. If a graveyard has twenty or more cards in it, draw three cards instead.

Humble the Brute

Destroy target creature with power 4 or greater.
Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Trail of Evidence

Whenever you cast an instant or sorcery spell, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Unwind

Counter target noncreature spell. Untap up to three lands.

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

Memory Erosion

Whenever an opponent casts a spell, that player mills two cards.

Hold for Questioning

Enchant creature or planeswalker
When Hold for Questioning enters the battlefield, tap enchanted permanent and investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Enchanted permanent doesn't untap during its controller's untap step and its activated abilities can't be activated.

Perpetual Timepiece

{T}: Mill two cards.
{2}, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

Stroke of Genius

Didn't Say Please

Counter target spell. Its controller mills three cards.

Countermand

Counter target spell. Its controller mills four cards.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Etherium Sculptor

Artifact spells you cast cost {1} less to cast.

Wizards of Thay

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token that's a copy of this creature that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Instant and sorcery spells you cast cost {1} less to cast.
You may cast sorcery spells as though they had flash.

Ethereal Investigator

Flying
When Ethereal Investigator enters the battlefield, investigate X times, where X is the number of opponents you have. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you draw your second card each turn, create a 1/1 white Spirit creature token with flying.

Mirrormade

You may have Mirrormade enter the battlefield as a copy of any artifact or enchantment on the battlefield.

Ghostly Prison

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

Traumatize

Target player mills half their library, rounded down.

Dream Twist

Target player mills three cards.
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Tribute Mage

When Tribute Mage enters the battlefield, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.

Fleeting Memories

When Fleeting Memories enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, target player mills three cards.

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Buried Ruin: Return target artifact card from your graveyard to your hand.

Grand Arbiter Augustin IV

White spells you cast cost {1} less to cast.
Blue spells you cast cost {1} less to cast.
Spells your opponents cast cost {1} more to cast.

Scavenger Grounds

{T}: Add {C}.
{2}, {T}, Sacrifice a Desert: Exile all graveyards.

Keening Stone

{5}, {T}: Target player mills X cards, where X is the number of cards in that player's graveyard.

Mangara, the Diplomat

Lifelink
Whenever an opponent attacks with creatures, if two or more of those creatures are attacking you and/or planeswalkers you control, draw a card.
Whenever an opponent casts their second spell each turn, draw a card.

Patient Rebuilding

At the beginning of your upkeep, target opponent mills three cards, then you draw a card for each land card put into their graveyard this way.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Starfield Mystic

Enchantment spells you cast cost {1} less to cast.
Whenever an enchantment you control is put into a graveyard from the battlefield, put a +1/+1 counter on Starfield Mystic.

Expedition Map

{2}, {T}, Sacrifice Expedition Map: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Fleet Swallower

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

Desert

{T}: Add {C}.
{T}: Desert deals 1 damage to target attacking creature. Activate only during the end of combat step.

Tome Scour

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.

Solve the Equation

Search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Into the Story

This spell costs {3} less to cast if an opponent has seven or more cards in their graveyard.
Draw four cards.

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.

Ghostly Castigator

Flying
When Ghostly Castigator enters the battlefield, you may shuffle up to three target cards from your graveyard into your library.
If Ghostly Castigator would be put into a graveyard from anywhere, exile it instead.

Covetous Castaway

When Covetous Castaway dies, mill three cards. (Put the top three cards of your library into your graveyard.)
Disturb {3}{U}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Covetous Castaway // Ghostly Castigator

Court of Cunning

When Court of Cunning enters the battlefield, you become the monarch.
At the beginning of your upkeep, any number of target players each mill two cards. If you're the monarch, each of those players mills ten cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Mechanized Production

Enchant artifact you control
At the beginning of your upkeep, create a token that's a copy of enchanted artifact. Then if you control eight or more artifacts with the same name as one another, you win the game.

Calamity's Wake

Exile all graveyards. Players can't cast noncreature spells this turn. Exile Calamity's Wake.

Mistgate Pathway

Hengegate Pathway

Hengegate Pathway // Mistgate Pathway

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Azorius Guildgate

Azorius Guildgate enters the battlefield tapped.
{T}: Add {W} or {U}.

Triskaidekaphile

You have no maximum hand size.
At the beginning of your upkeep, if you have exactly thirteen cards in your hand, you win the game.
{3}{U}: Draw a card.

Academy Ruins

{T}: Add {C}.
{1}{U}, {T}: Put target artifact card from your graveyard on top of your library.

Jace, the Perfected Mind

Compleated ({U/P} can be paid with {U} or 2 life. If life was paid, this planeswalker enters with two fewer loyalty counters.)
+1: Until your next turn, up to one target creature gets -3/-0.
−2: Target player mills three cards. Then if a graveyard has twenty or more cards in it, you draw three cards. Otherwise, you draw a card.
−X: Target player mills three times X cards.

Reparations

Whenever an opponent casts a spell that targets you or a creature you control, you may draw a card.

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

Mind Sculpt

Vexilus Praetor

Flash
Vigilance
Aegis of the Emperor — Commanders you control have protection from everything.

Curiosity Crafter

Flying
You have no maximum hand size.
Whenever a creature token you control deals combat damage to a player, draw a card.

Return to Dust

Exile target artifact or enchantment. If you cast this spell during your main phase, you may exile up to one other target artifact or enchantment.

Undead Alchemist

If a Zombie you control would deal combat damage to a player, instead that player mills that many cards.
Whenever a creature card is put into an opponent's graveyard from their library, exile that card and create a 2/2 black Zombie creature token.

Mesa Enchantress

Whenever you cast an enchantment spell, you may draw a card.

Psychic Spiral

Shuffle all cards from your graveyard into your library. Target player mills that many cards.