Blizzard Specter

Flying
Whenever Blizzard Specter deals combat damage to a player, choose one —
• That player returns a permanent they control to its owner's hand.
• That player discards a card.

Saddled Rimestag

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

Snow-Covered Island

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.

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.)

Snow-Covered Forest

Dead of Winter

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

Rimescale Dragon

Flying
{2}{S}: Tap target creature and put an ice counter on it. ({S} can be paid with one mana from a snow source.)
Creatures with ice counters on them don't untap during their controllers' untap steps.

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.

Snow-Covered Swamp

Into the North

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

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.

Migration Path

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.
Cycling {2} ({2}, Discard this card: Draw a card.)