Cover of Winter

Cumulative upkeep {S} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it. {S} can be paid with one mana from a snow source.)
If a creature would deal combat damage to you and/or one or more creatures you control, prevent X of that damage, where X is the number of age counters on Cover of Winter.
{S}: Put an age counter on Cover of Winter.

Bear Umbra

Enchant creature
Enchanted creature gets +2/+2 and has "Whenever this creature attacks, untap all lands you control."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Wall of Shards

Defender, flying
Cumulative upkeep—An opponent gains 1 life. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Boreal Druid

Rime Tender

{T}: Untap another target snow permanent.

Glacial Plating

Enchant creature
Cumulative upkeep {S} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it. {S} can be paid with one mana from a snow source.)
Enchanted creature gets +3/+3 for each age counter on Glacial Plating.

Glittering Frost

Enchant land
Enchanted land is snow.
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Last March of the Ents

This spell can't be countered.
Draw cards equal to the greatest toughness among creatures you control, then put any number of creature cards from your hand onto the battlefield.

Ice-Fang Coatl

Flash
Flying
When Ice-Fang Coatl enters, draw a card.
Ice-Fang Coatl has deathtouch as long as you control at least three other snow permanents.

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.)

Case of the Locked Hothouse

You may play an additional land on each of your turns.
To solve — You control seven or more lands. (If unsolved, solve at the beginning of your end step.)
Solved — You may look at the top card of your library any time, and you may play lands and cast creature and enchantment spells from the top of your library.

Oracle of Mul Daya

You may play an additional land on each of your turns.
Play with the top card of your library revealed.
You may play lands from the top of your library.

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Mirari's Wake

Creatures you control get +1/+1.
Whenever you tap a land for mana, add one mana of any type that land produced.

Coldsteel Heart

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

Frost Augur

{S}, {T}: Look at the top card of your library. If it's a snow card, you may reveal it and put it into your hand. ({S} can be paid with one mana from a snow source.)

Blizzard Strix

Flash
Flying
When Blizzard Strix enters, if you control another snow permanent, exile target permanent other than Blizzard Strix. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Iceberg Cancrix

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

Frostwalla

{S}: Frostwalla gets +2/+2 until end of turn. Activate only once each turn. ({S} can be paid with one mana from a snow source.)

Hunter's Prowess

Until end of turn, target creature gets +3/+3 and gains trample and "Whenever this creature deals combat damage to a player, draw that many cards."

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.

Gelid Shackles

Enchant creature
Enchanted creature can't block, and its activated abilities can't be activated.
{S}: Enchanted creature gains defender until end of turn. ({S} can be paid with one mana from a snow source.)

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."

Ohran Frostfang

Attacking creatures you control have deathtouch.
Whenever a creature you control deals combat damage to a player, draw a card.

Glacial Revelation

Reveal the top six cards of your library. You may put any number of snow permanent cards from among them into your hand. Put the rest into your graveyard.

Squall Drifter

Rishkar's Expertise

Draw cards equal to the greatest power among creatures you control.
You may cast a spell with mana value 5 or less from your hand without paying its mana cost.

Druid Class

(Gain the next level as a sorcery to add its ability.)
Landfall — Whenever a land you control enters, you gain 1 life.
{2}{G}: Level 2
You may play an additional land on each of your turns.
{4}{G}: Level 3
When this Class becomes level 3, target land you control becomes a creature with haste and "This creature's power and toughness are each equal to the number of lands you control." It's still a land.

Vega, the Watcher

Flying
Whenever you cast a spell from anywhere other than your hand, draw a card.

Snow-Covered Forest

Pilfering Hawk

Flying
{S}, {T}: Draw a card, then discard a card. ({S} can be paid with one mana from a snow source.)

Frost Raptor

Flying
{S}{S}: Frost Raptor gains shroud until end of turn. ({S} can be paid with one mana from a snow source. A creature with shroud can't be the target of spells or abilities.)

Exploration

You may play an additional land on each of your turns.

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.)

Centaur Omenreader

As long as Centaur Omenreader is tapped, creature spells you cast cost {2} less to cast.

Icebind Pillar

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

Traverse the Outlands

Search your library for up to X basic land cards, where X is the greatest power among creatures you control. Put those cards onto the battlefield tapped, then shuffle.

Ohran Viper

Whenever Ohran Viper deals combat damage to a creature, destroy that creature at end of combat.
Whenever Ohran Viper deals combat damage to a player, you may draw a card.

Frostpeak Yeti

{1}{S}: Frostpeak Yeti can't be blocked this turn. ({S} can be paid with one mana from a snow source.)

Icehide Golem

({S} can be paid with one mana from a snow source.)

Sylvan Awakening

Until your next turn, all lands you control become 2/2 Elemental creatures with reach, indestructible, and haste. They're still lands.

Blizzard Brawl

Choose target creature you control and target creature you don't control. If you control three or more snow permanents, the creature you control gets +1/+0 and gains indestructible until end of turn. Then those creatures fight each other. (Each deals damage equal to its power to the other.)

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.

Moritte of the Frost

Changeling (This card is every creature type.)
You may have Moritte of the Frost enter as a copy of a permanent you control, except it's legendary and snow in addition to its other types and, if it's a creature, it enters with two additional +1/+1 counters on it and has changeling.

Saddled Rimestag

Saddled Rimestag gets +2/+2 as long as you had another creature enter the battlefield under your control this turn.

Sculptor of Winter

Blessing of Frost

Distribute X +1/+1 counters among any number of creatures you control, where X is the amount of {S} spent to cast this spell. Then draw a card for each creature you control with power 4 or greater.

Search for Glory

Search your library for a snow permanent card, a legendary card, or a Saga card, reveal it, put it into your hand, then shuffle. You gain 1 life for each {S} spent to cast this spell. ({S} is mana from a snow source.)

Snow-Covered Island

Boreal Centaur

{S}: Boreal Centaur gets +1/+1 until end of turn. Activate only once each turn. ({S} can be paid with one mana from a snow source.)

Wayward Swordtooth

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
You may play an additional land on each of your turns.
Wayward Swordtooth can't attack or block unless you have the city's blessing.

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.

Abominable Treefolk

Trample
Abominable Treefolk's power and toughness are each equal to the number of snow permanents you control.
When Abominable Treefolk enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Conifer Wurm

Trample
{3}{G}: Conifer Wurm gets +X/+X until end of turn, where X is the number of snow permanents you control.

Frostweb Spider

Reach (This creature can block creatures with flying.)
Whenever Frostweb Spider blocks a creature with flying, put a +1/+1 counter on Frostweb Spider at end of combat.

Phyrexian Ironfoot

Phyrexian Ironfoot doesn't untap during your untap step.
{1}{S}: Untap Phyrexian Ironfoot. ({S} can be paid with one mana from a snow source.)

Spirit of the Aldergard

When Spirit of the Aldergard enters, search your library for a snow land card, reveal it, put it into your hand, then shuffle.
Spirit of the Aldergard gets +1/+0 for each other snow permanent you control.

Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

Isu the Abominable

You may look at the top card of your library any time.
You may play snow lands and cast snow spells from the top of your library.
Whenever another snow permanent you control enters, you may pay {G}, {W}, or {U}. If you do, put a +1/+1 counter on Isu the Abominable.

Return of the Wildspeaker

Choose one —
• Draw cards equal to the greatest power among non-Human creatures you control.
• Non-Human creatures you control get +3/+3 until end of turn.

Diamond Faerie

Flying
{1}{S}: Snow creatures you control get +1/+1 until end of turn. ({S} can be paid with one mana from a snow source.)

Felidar Retreat

Landfall — Whenever a land you control enters, choose one —
• Create a 2/2 white Cat Beast creature token.
• Put a +1/+1 counter on each creature you control. Those creatures gain vigilance until end of turn.

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.

Approach of the Second Sun

If this spell was cast from your hand and you've cast another spell named Approach of the Second Sun this game, you win the game. Otherwise, put Approach of the Second Sun into its owner's library seventh from the top and you gain 7 life.

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.

Icehide Troll

{S}{S}: Icehide Troll gets +2/+0 and gains indestructible until end of turn. Tap it. (Damage and effects that say "destroy" don't destroy it. {S} can be paid with one mana from a snow source.)

Overwhelming Stampede

Until end of turn, creatures you control gain trample and get +X/+X, where X is the greatest power among creatures you control.

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."

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.)

Snow-Covered Plains

Boreal Outrider

Whenever you cast a creature spell, if {S} of any of that spell's colors was spent to cast it, that creature enters with an additional +1/+1 counter on it. ({S} is mana from a snow source.)

Arcum's Astrolabe

({S} can be paid with one mana from a snow source.)
When Arcum's Astrolabe enters, draw a card.
{1}, {T}: Add one mana of any color.