Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Zellix, Sanity Flayer

Hive Mind — Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.
{1}, {T}: Target player mills three cards.
Choose a Background (You can have a Background as a second commander.)

Sapphire Medallion

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

Arcane Signet

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

Sol Ring

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Mindcrank

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

Cranial Archive

{2}, Exile Cranial Archive: Target player shuffles their graveyard into their library. Draw a card.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Roadside Reliquary

{T}: Add {C}.
{2}, {T}, Sacrifice Roadside Reliquary: Draw a card if you control an artifact. Draw a card if you control an enchantment.

Copy Enchantment

You may have Copy Enchantment enter as a copy of any enchantment on the battlefield.

Soul-Guide Lantern

When this artifact enters, exile target card from a graveyard.
{T}, Sacrifice this artifact: Exile each opponent's graveyard.
{1}, {T}, Sacrifice this artifact: Draw a card.

Folio of Fancies

Players have no maximum hand size.
{X}{X}, {T}: Each player draws X cards.
{2}{U}, {T}: Each opponent mills cards equal to the number of cards in their hand.

Buried Ruin

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

Worry Beads

At the beginning of each player's upkeep, that player mills a card.

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Neurok Stealthsuit

Equipped creature has shroud. (It can't be the target of spells or abilities.)
{U}{U}: Attach Neurok Stealthsuit to target creature you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Drown in Dreams

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Target player draws X cards.
• Target player mills twice X cards.

Court of Cunning

When Court of Cunning enters, 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.)

Spark Double

You may have Spark Double enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Winged Boots

Equipped creature has flying and ward {4}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}.)
Equip {1}

Psychic Corrosion

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

Island

Crush of Tentacles

Surge {3}{U}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Return all nonland permanents to their owners' hands. If this spell's surge cost was paid, create an 8/8 blue Octopus creature token.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Witness Protection

Enchant creature
Enchanted creature loses all abilities and is a green and white Citizen creature with base power and toughness 1/1 named Legitimate Businessperson. (It loses all other colors, card types, creature types, and names.)

Ravenform

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

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.

Counterspell

Mesmeric Orb

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

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Drowned Secrets

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

Visions of Beyond

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

Chart a Course

Draw two cards. Then discard a card unless you attacked this turn.

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards.

Curse of the Swine

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Cryptic Command

Choose two —
• Counter target spell.
• Return target permanent to its owner's hand.
• Tap all creatures your opponents control.
• Draw a card.

Ghoulcaller's Bell

Castle Vantress

Castle Vantress enters tapped unless you control an Island.
{T}: Add {U}.
{2}{U}{U}, {T}: Scry 2.

Imprisoned in the Moon

Enchant creature, land, or planeswalker
Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.

Sword of Body and Mind

Equipped creature gets +2/+2 and has protection from green and from blue.
Whenever equipped creature deals combat damage to a player, you create a 2/2 green Wolf creature token and that player mills ten cards.
Equip {2}

Divination

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice Idol of Oblivion: Create a 10/10 colorless Eldrazi creature token.

Tyrite Sanctum

{T}: Add {C}.
{2}, {T}: Target legendary creature becomes a God in addition to its other types. Put a +1/+1 counter on it.
{4}, {T}, Sacrifice Tyrite Sanctum: Put an indestructible counter on target God.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Tetsuko Umezawa, Fugitive

Creatures you control with power or toughness 1 or less can't be blocked.

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.

Scavenger Grounds

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

In Too Deep

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Enchant creature, planeswalker, or Clue
Enchanted permanent is a colorless Clue artifact with "{2}, Sacrifice this artifact: Draw a card" and loses all other abilities. (It's no longer a creature or planeswalker.)

Memory Erosion

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

Persistent Nightmare

Skulk (This creature can't be blocked by creatures with greater power.)
When Persistent Nightmare deals combat damage to a player, return it to its owner's hand.

Startled Awake

Target opponent mills thirteen cards.
{3}{U}{U}: Put Startled Awake from your graveyard onto the battlefield transformed. Activate only as a sorcery.

Startled Awake // Persistent Nightmare

Maddening Cacophony

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

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

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.

Negate

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

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.

Plaza of Heroes

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell.
{T}: Add one mana of any color among legendary permanents you control.
{3}, {T}, Exile Plaza of Heroes: Target legendary creature gains hexproof and indestructible until end of turn.

Dreamborn Muse

At the beginning of each player's upkeep, that player mills X cards, where X is the number of cards in their hand.

Manic Scribe

When Manic Scribe enters, 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.

Ipnu Rivulet

{T}: Add {C}.
{T}, Pay 1 life: Add {U}.
{1}{U}, {T}, Sacrifice a Desert: Target player mills four cards. (They put the top four cards of their library into their graveyard.)

Bruvac the Grandiloquent

If an opponent would mill one or more cards, they mill twice that many cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Devastation Tide

Return all nonland permanents to their owners' hands.
Miracle {1}{U} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Dispel

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.

Riddlekeeper

Whenever a creature attacks you or a planeswalker you control, that creature's controller mills two cards.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Demolition Field

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Destroy target nonbasic land an opponent controls. That land's controller may search their library for a basic land card, put it onto the battlefield, then shuffle. You may search your library for a basic land card, put it onto the battlefield, then shuffle.

Awoken Horror

When this creature transforms into Awoken Horror, return all non-Horror creatures to their owners' hands.

Thing in the Ice

Defender
Thing in the Ice enters with four ice counters on it.
Whenever you cast an instant or sorcery spell, remove an ice counter from Thing in the Ice. Then if it has no ice counters on it, transform it.

Thing in the Ice // Awoken Horror

Ruin Crab

Landfall — Whenever a land you control enters, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Halimar Depths

Halimar Depths enters tapped.
When Halimar Depths enters, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

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.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Archmage's Charm

Choose one —
• Counter target spell.
• Target player draws two cards.
• Gain control of target nonland permanent with mana value 1 or less.

Grindstone

{3}, {T}: Target player mills two cards. If two cards that share a color were milled this way, repeat this process.