Muddle the Mixture

Counter target instant or sorcery spell.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Rimewind Taskmage

{1}, {T}: You may tap or untap target permanent. Activate only if you control four or more snow permanents.

Counterspell

Marit Lage's Slumber

Whenever Marit Lage's Slumber or another snow permanent you control enters, scry 1.
At the beginning of your upkeep, if you control ten or more snow permanents, sacrifice Marit Lage's Slumber. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

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

Quiet Contemplation

Whenever you cast a noncreature spell, you may pay {1}. If you do, tap target creature an opponent controls and it doesn't untap during its controller's next untap step.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Rimefeather Owl

Flying
Rimefeather Owl's power and toughness are each equal to the number of snow permanents on the battlefield.
{1}{S}: Put an ice counter on target permanent.
Permanents with ice counters on them are snow.

Orb of Dreams

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Ghost Quarter

{T}: Add {C}.
{T}, Sacrifice Ghost Quarter: Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Whir of Invention

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

Meloku the Clouded Mirror

Flying
{1}, Return a land you control to its owner's hand: Create a 1/1 blue Illusion creature token with flying.

Echoing Truth

Return target nonland permanent and all other permanents with the same name as that permanent to their owners' hands.

Seer's Lantern

{T}: Add {C}.
{2}, {T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Coldsteel Heart

Coldsteel Heart enters tapped.
As Coldsteel Heart enters, choose a color.
{T}: Add one mana of the chosen color.

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.

Inkwell Leviathan

Trample
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Shroud (This creature can't be the target of spells or abilities.)

Inventors' Fair

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
{T}: Add {C}.
{4}, {T}, Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Unsubstantiate

Return target spell or creature to its owner's hand.

Nevinyrral's Disk

Nevinyrral's Disk enters tapped.
{1}, {T}: Destroy all artifacts, creatures, and enchantments.

Sequestered Stash

{T}: Add {C}.
{4}, {T}, Sacrifice Sequestered Stash: Mill five cards. Then you may put an artifact card from your graveyard on top of your library.

Stroke of Genius

Desert of the Mindful

Desert of the Mindful enters tapped.
{T}: Add {U}.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)

Negate

Rise from the Tides

Create a tapped 2/2 black Zombie creature token for each instant and sorcery card in your graveyard.

Second Wind

Enchant creature
{T}: Tap enchanted creature.
{T}: Untap enchanted creature.

Lazotep Plating

Amass Zombies 1. (Put a +1/+1 counter 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.)
You and permanents you control gain hexproof until end of turn. (You and they can't be the targets of spells or abilities your opponents control.)

Remote Isle

Remote Isle enters tapped.
{T}: Add {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Illusionist's Bracers

Whenever an ability of equipped creature is activated, if it isn't a mana ability, copy that ability. You may choose new targets for the copy.
Equip {3}

Deep Freeze

Enchant creature
Enchanted creature has base power and toughness 0/4, has defender, loses all other abilities, and is a blue Wall in addition to its other colors and types.

Prohibit

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Counter target spell if its mana value is 2 or less. If this spell was kicked, counter that spell if its mana value is 4 or less instead.

Blink of an Eye

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Return target nonland permanent to its owner's hand. If this spell was kicked, draw a card.

Snow-Covered Island

Quicksilver Fountain

At the beginning of each player's upkeep, that player puts a flood counter on target non-Island land they control of their choice. That land is an Island for as long as it has a flood counter on it.
At the beginning of each end step, if all lands on the battlefield are Islands, remove all flood counters from them.

Stolen Goods

Target opponent exiles cards from the top of their library until they exile a nonland card. Until end of turn, you may cast that card without paying its mana cost.

Iceberg Cancrix

Whenever another snow permanent you control enters, you may have target player mill two cards.

Sage's Row Denizen

Whenever another blue creature you control enters, target player mills two cards.

Aetherspouts

For each attacking creature, its owner puts it on their choice of the top or bottom of their library.

Portal Mage

Flash
When Portal Mage enters during the declare attackers step, you may reselect which player or permanent target attacking creature is attacking. (It can't attack its controller or their permanents.)

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Telling Time

Look at the top three cards of your library. Put one of those cards into your hand, one on top of your library, and one on the bottom of your library.

Anticipate

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.
When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Monastery Siege

As Monastery Siege enters, choose Khans or Dragons.
• Khans — At the beginning of your draw step, draw an additional card, then discard a card.
• Dragons — Spells your opponents cast that target you or a permanent you control cost {2} more to cast.

Retreat to Coralhelm

Landfall — Whenever a land you control enters, choose one —
• You may tap or untap target creature.
• Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Stasis

Players skip their untap steps.
At the beginning of your upkeep, sacrifice Stasis unless you pay {U}.

Coral Atoll

Coral Atoll enters tapped.
When Coral Atoll enters, sacrifice it unless you return an untapped Island you control to its owner's hand.
{T}: Add {C}{U}.

Boomerang

Return target permanent to its owner's hand.

Pilgrim's Eye

Flying
When Pilgrim's Eye enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Skyline Cascade

Skyline Cascade enters tapped.
When Skyline Cascade enters, target creature an opponent controls doesn't untap during its controller's next untap step.
{T}: Add {U}.

Aetherize

Return all attacking creatures to their owner's hand.

Lonely Sandbar

Lonely Sandbar enters tapped.
{T}: Add {U}.
Cycling {U} ({U}, Discard this card: Draw a card.)

Darksteel Citadel

Deep-Sea Kraken

Deep-Sea Kraken can't be blocked.
Suspend 9—{2}{U} (Rather than cast this card from your hand, you may pay {2}{U} and exile it with nine time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)
Whenever an opponent casts a spell, if Deep-Sea Kraken is suspended, remove a time counter from it.

Sigiled Starfish

{T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Isochron Scepter

Imprint — When Isochron Scepter enters, you may exile an instant card with mana value 2 or less from your hand.
{2}, {T}: You may copy the exiled card. If you do, you may cast the copy without paying its mana cost.

Tamiyo's Journal

At the beginning of your upkeep, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
{T}, Sacrifice three Clues: Search your library for a card, put that card into your hand, then shuffle.

Blinkmoth Well

{T}: Add {C}.
{2}, {T}: Tap target noncreature artifact.

Rapid Hybridization

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

Fog Bank

Defender (This creature can't attack.)
Flying
Prevent all combat damage that would be dealt to and dealt by this creature.

Ovinize

Until end of turn, target creature loses all abilities and has base power and toughness 0/1.

Rimewind Cryomancer

{1}, {T}: Counter target activated ability. Activate only if you control four or more snow permanents. (Mana abilities can't be targeted.)

Reality Acid

Enchant permanent
Vanishing 3 (This Aura enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Reality Acid leaves the battlefield, enchanted permanent's controller sacrifices it.

Pongify

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

Grip of Phyresis

Gain control of target Equipment, then create a 0/0 black Phyrexian Germ creature token and attach that Equipment to it.

Snap

Return target creature to its owner's hand. Untap up to two lands.

Sky Diamond

Curse of Verbosity

Enchant player
Whenever enchanted player is attacked, you draw a card. Each opponent attacking that player does the same.

Heidar, Rimewind Master

{2}, {T}: Return target permanent to its owner's hand. Activate only if you control four or more snow permanents.

Into the Roil

Domineering Will

Target player gains control of up to three target nonattacking creatures until end of turn. Untap those creatures. They block this turn if able.