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.

Ronom Serpent

Ronom Serpent can't attack unless defending player controls a snow land.
When you control no snow lands, sacrifice Ronom Serpent.

Into the North

Search your library for a snow land card, put it onto the battlefield tapped, then shuffle.

Kaldring, the Rimestaff

{T}: You may play target snow permanent card from your graveyard this turn. If you do, it enters tapped.

Jorn, God of Winter

Whenever Jorn attacks, untap each snow permanent you control.

Jorn, God of Winter // Kaldring, the Rimestaff

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.)

Snow-Covered Forest

Snow-Covered Plains

Snow-Covered Island

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.

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.

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.)

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.

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.)