Leyline of Anticipation

If Leyline of Anticipation is in your opening hand, you may begin the game with it on the battlefield.
You may cast spells as though they had flash.

Marit Lage's Slumber

Whenever Marit Lage's Slumber or another snow permanent enters the battlefield under your control, 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.

Rime Tender

{T}: Untap another target snow permanent.

Ice-Fang Coatl

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

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Dead of Winter

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

Sculptor of Winter

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Sol Ring

Kaldring, the Rimestaff

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

Jorn, God of Winter

Whenever Jorn attacks, untap each snow permanent you control.

Jorn, God of Winter // Kaldring, the Rimestaff

Into the North

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

Boreal Druid

Coldsteel Heart

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

Villainous Wealth

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Rimewind Cryomancer

{1}, {T}: Counter target activated ability. Activate only if you control four or more snow permanents. (Mana abilities can't be targeted.)