Some Disassembly Required

{B}, Sacrifice a creature: Distribute the sacrificed creature's keyword abilities among any number of other target creatures until end of turn. If it's December, you gain 1 life for each of those keywords.

Blood on the Snow

Choose one —
• Destroy all creatures.
• Destroy all planeswalkers.
Then return a creature or planeswalker card with mana value X or less from your graveyard to the battlefield, where X is the amount of {S} spent to cast this spell. ({S} is mana from a snow source.)

Mouth of Ronom

{T}: Add {C}.
{4}{S}, {T}, Sacrifice Mouth of Ronom: It deals 4 damage to target creature. ({S} can be paid with one mana from a snow source.)

Priest of the Haunted Edge

{T}, Sacrifice Priest of the Haunted Edge: Target creature gets -X/-X until end of turn, where X is the number of snow lands you control. Activate only as a sorcery.

Phyrexian Soulgorger

Cumulative upkeep—Sacrifice a creature. (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.)

Break the Ice

Destroy target land that is snow or could produce {C}.
Overload {4}{B}{B} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Snow-Covered Swamp

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.

Scrying Sheets

{T}: Add {C}.
{1}{S}, {T}: Look at the top card of your library. If that card is snow, you may reveal it and put it into your hand. ({S} can be paid with one mana from a snow source.)

Frost Marsh

Frost Marsh enters tapped.
{T}: Add {U} or {B}.

Thopter Pie Network

At the beginning of your upkeep, if you're eating, create a 1/1 colorless Thopter artifact creature token with flying. Use food to represent the token.
Whenever a creature token you control dies, if it's represented by food, eat it.

Master of Death

When Master of Death enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
At the beginning of your upkeep, if Master of Death is in your graveyard, you may pay 1 life. If you do, return it to your hand.

Narfi, Betrayer King

Other snow and Zombie creatures you control get +1/+1.
{S}{S}{S}: Return Narfi, Betrayer King from your graveyard to the battlefield tapped. ({S} can be paid with one mana from a snow source.)

Gifts Given

Search target opponent's library for four cards with different names and reveal them. That player chooses two of those cards. Put the chosen cards into the player's graveyard and the rest into your hand. Then that player shuffles their library.

Present Arms

Exchange your library with another deck you own from outside the game. Shuffle your library.

Decorated Knight

Whenever Decorated Knight attacks, draw a card from your original deck if it's outside the game.

Decorated Knight // Present Arms

Bog Humbugs

Flying
Whenever Bog Humbugs deals combat damage, hum that many notes of a festive song. If you can, put a +1/+1 counter on Bog Humbugs.

Mishra's Toy Workshop

{T}: Add {C}{C}{C}. Spend this mana only on spells and abilities that put tokens onto the battlefield. Use toys to represent the tokens.

Snow-Covered Island

Draugr Necromancer

If a nontoken creature an opponent controls would die, exile that card with an ice counter on it instead.
You may cast spells from among cards in exile your opponents own with ice counters on them, and you may spend mana from snow sources as though it were mana of any color to cast those spells.

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.)

Dark Depths

Dark Depths enters with ten ice counters on it.
{3}: Remove an ice counter from Dark Depths.
When Dark Depths has no ice counters on it, sacrifice it. If you do, create Marit Lage, a legendary 20/20 black Avatar creature token with flying and indestructible.

Gutless Ghoul

{1}, Sacrifice a creature: You gain 2 life.

Evil Presents

Put a creature card from your hand into play under target opponent's control. That creature attacks each turn if able . . . and always attacks its controller.

Last-Minute Chopping

Ask target opponent if they remembered to get you a present. If they say yes, they put a card they own from outside the game into your hand. Otherwise, you gain control of target permanent they control.

Dead of Winter

All nonsnow creatures get -X/-X until end of turn, where X is the number of snow permanents you control.

Dreadhound

When Dreadhound enters, mill three cards. (Put the top three cards of your library into your graveyard.)
Whenever a creature dies or a creature card is put into a graveyard from a library, each opponent loses 1 life.

Ice Tunnel

({T}: Add {U} or {B}.)
Ice Tunnel enters tapped.

Heidar, Rimewind Master

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

Stocking Tiger

Stocking Tiger enters with a sealed Magic booster pack under it.
When Stocking Tiger deals combat damage to a player, unwrap the booster pack and put it into your hand.

Grimgrin, Corpse-Born

Grimgrin, Corpse-Born enters tapped and doesn't untap during your untap step.
Sacrifice another creature: Untap Grimgrin and put a +1/+1 counter on it.
Whenever Grimgrin attacks, destroy target creature defending player controls, then put a +1/+1 counter on Grimgrin.