Hylda of the Icy Crown

Whenever you tap an untapped creature an opponent controls, you may pay {1}. When you do, choose one —
• Create a 4/4 white and blue Elemental creature token.
• Put a +1/+1 counter on each creature you control.
• Scry 2, then draw a card.

Icy Prison

When Icy Prison enters, exile target creature.
At the beginning of your upkeep, sacrifice Icy Prison unless any player pays {3}.
When Icy Prison leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Avalanche Caller

{2}: Target snow land you control becomes a 4/4 Elemental creature with hexproof and haste until end of turn. It's still a land. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

Snow-Covered Island

Winter's Chill

Cast this spell only during combat before blockers are declared.
X can't be greater than the number of snow lands you control.
Choose X target attacking creatures. For each of those creatures, its controller may pay {1} or {2}. If that player doesn't, destroy that creature at end of combat. If that player pays only {1}, prevent all combat damage that would be dealt to and dealt by that creature this combat.

Crippling Chill

Tap target creature. It doesn't untap during its controller's next untap step.
Draw a card.

Icy Blast

Tap X target creatures.
Ferocious — If you control a creature with power 4 or greater, those creatures don't untap during their controllers' next untap steps.

Faceless Haven

{T}: Add {C}.
{S}{S}{S}: Faceless Haven becomes a 4/3 creature with vigilance and all creature types until end of turn. It's still a land. ({S} can be paid with one mana from a snow source.)

Icy Manipulator

{1}, {T}: Tap target artifact, creature, or land.

Berg Strider

When Berg Strider enters, tap target artifact or creature an opponent controls. If {S} was spent to cast this spell, that permanent doesn't untap during its controller's next untap step. ({S} is mana from a snow source.)

Glacial Floodplain

({T}: Add {W} or {U}.)
Glacial Floodplain enters tapped.

Graven Lore

Scry X, where X is the amount of {S} spent to cast this spell, then draw three cards. ({S} is mana from a snow source.)

Boreal Shelf

Boreal Shelf enters tapped.
{T}: Add {W} or {U}.

Chilling Grasp

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.
Madness {3}{U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Glaciers

At the beginning of your upkeep, sacrifice Glaciers unless you pay {W}{U}.
All Mountains are Plains.

Replicating Ring

{T}: Add one mana of any color.
At the beginning of your upkeep, put a night counter on Replicating Ring. Then if it has eight or more night counters on it, remove all of them and create eight colorless snow artifact tokens named Replicated Ring with "{T}: Add one mana of any color."

Ray of Frost

Flash
Enchant creature
When Ray of Frost enters, if enchanted creature is red, tap it.
As long as enchanted creature is red, it loses all abilities.
Enchanted creature doesn't untap during its controller's untap step.

On Thin Ice

Enchant snow land you control
When On Thin Ice enters, exile target creature an opponent controls until On Thin Ice leaves the battlefield.

Cave of the Frost Dragon

If you control two or more other lands, Cave of the Frost Dragon enters tapped.
{T}: Add {W}.
{4}{W}: Cave of the Frost Dragon becomes a 3/4 white Dragon creature with flying until end of turn. It's still a land.

Flashfreeze

Heidar, Rimewind Master

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

Chillbringer

Flying
When Chillbringer enters, tap target creature an opponent controls. It doesn't untap during its controller's next untap step.

Icebind Pillar

{S}, {T}: Tap target artifact or creature. ({S} can be paid with one mana from a snow source.)

Ascendant Spirit

{S}{S}: Ascendant Spirit becomes a Spirit Warrior with base power and toughness 2/3.
{S}{S}{S}: If Ascendant Spirit is a Warrior, put a flying counter on it and it becomes a Spirit Warrior Angel with base power and toughness 4/4.
{S}{S}{S}{S}: If Ascendant Spirit is an Angel, put two +1/+1 counters on it and it gains "Whenever this creature deals combat damage to a player, draw a card."

Frost Titan

Whenever Frost Titan becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {2}.
Whenever Frost Titan enters or attacks, tap target permanent. It doesn't untap during its controller's next untap step.

Winter's Rest

Enchant creature
When Winter's Rest enters, tap enchanted creature.
As long as you control another snow permanent, enchanted creature doesn't untap during its controller's untap step.

Chillerpillar

{4}{S}{S}: Monstrosity 2. (If this creature isn't monstrous, put two +1/+1 counters on it and it becomes monstrous. {S} can be paid with one mana from a snow source.)
As long as Chillerpillar is monstrous, it has flying.

Cleric of Chill Depths

Whenever Cleric of Chill Depths blocks a creature, that creature doesn't untap during its controller's next untap step.

Rimewind Taskmage

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

Frost Breath

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Swords to Plowshares

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

Snow-Covered Plains

Rimeshield Frost Giant

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)

Iceberg

Iceberg enters with X ice counters on it.
{3}: Put an ice counter on Iceberg.
Remove an ice counter from Iceberg: Add {C}.

Coldsteel Heart

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

Icingdeath, Frost Tyrant

Flying, vigilance
When Icingdeath, Frost Tyrant dies, create Icingdeath, Frost Tongue, a legendary white Equipment artifact token with "Equipped creature gets +2/+0," "Whenever equipped creature attacks, tap target creature defending player controls," and equip {2}.

Icebreaker Kraken

This spell costs {1} less to cast for each snow land you control.
When Icebreaker Kraken enters, artifacts and creatures target opponent controls don't untap during that player's next untap step.
Return three snow lands you control to their owner's hand: Return Icebreaker Kraken to its owner's hand.

Frostfist Strider

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When Frostfist Strider enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Cone of Cold

Roll a d20.
1—9 | Tap all creatures your opponents control.
10—19 | Tap all creatures your opponents control. Those creatures don't untap during their controllers' next untap steps.
20 | Tap all creatures your opponents control. Those creatures don't untap during their controllers' next untap steps. Until your next turn, creatures your opponents control enter tapped.