Cold Snap

Cumulative upkeep {2} (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.)
At the beginning of each player's upkeep, this enchantment deals damage to that player equal to the number of snow lands they control.

Legions of Lim-Dûl

Snow swampwalk (This creature can't be blocked as long as defending player controls a snow Swamp.)

Ronom Hulk

Protection from snow
Cumulative upkeep {1} (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.)

Avalanche

Thermal Flux

Choose one —
• Target nonsnow permanent becomes snow until end of turn.
• Target snow permanent isn't snow until end of turn.
Draw a card at the beginning of the next turn's upkeep.

Rime Dryad

Snow forestwalk (This creature can't be blocked as long as defending player controls a snow Forest.)

Thermokarst

Destroy target land. If that land was a snow land, you gain 1 life.

Barbarian Guides

{2}{R}, {T}: Choose a land type. Target creature you control gains snow landwalk of the chosen type until end of turn. Return that creature to its owner's hand at the beginning of the next end step. (It can't be blocked as long as defending player controls a snow land of that type.)

Icequake

Destroy target land. If that land was a snow land, Icequake deals 1 damage to that land's controller.

Melting

Balduvian Frostwaker

{U}, {T}: Target snow land becomes a 2/2 blue Elemental creature with flying. It's still a land.

Arcum's Weathervane

{2}, {T}: Target snow land is no longer snow.
{2}, {T}: Target nonsnow basic land becomes snow.

Balduvian Conjurer

{T}: Target snow land becomes a 2/2 creature until end of turn. It's still a land.

Arctic Foxes

This creature can't be blocked by creatures with power 2 or greater as long as defending player controls a snow land.

Arcum's Sleigh

{2}, {T}: Target creature gains vigilance until end of turn. Activate only during combat and only if defending player controls a snow land.

Freyalise's Radiance

Cumulative upkeep {2} (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.)
Snow permanents don't untap during their controllers' untap steps.

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.

Arcum's Whistle

{3}, {T}: Choose target non-Wall creature the active player has controlled continuously since the beginning of the turn. That player may pay {X}, where X is that creature's mana value. If they don't pay, the creature attacks this turn if able, and at the beginning of the next end step, destroy it if it didn't attack this turn. Activate only before attackers are declared.

Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon enters, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.