Frostwalk Bastion

{T}: Add {C}.
{1}{S}: Until end of turn, Frostwalk Bastion becomes a 2/3 Construct artifact creature. It's still a land. ({S} can be paid with one mana from a snow source.)
Whenever Frostwalk Bastion deals combat damage to a creature, tap that creature and it doesn't untap during its controller's next untap step.

Hogaak, Arisen Necropolis

You can't spend mana to cast this spell.
Convoke, delve (Each creature you tap while casting this spell pays for {1} or one mana of that creature's color. Each card you exile from your graveyard pays for {1}.)
You may cast Hogaak, Arisen Necropolis from your graveyard.
Trample

Pondering Mage

When Pondering Mage enters, look at the top three cards of your library, then put them back in any order. You may shuffle. Draw a card.

Pyrophobia

Pyrophobia deals 3 damage to target creature. Cowards can't block this turn.

Nature's Chant

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Igneous Elemental

This spell costs {2} less to cast if there is a land card in your graveyard.
When Igneous Elemental enters, you may have it deal 2 damage to target creature.

Rime Tender

{T}: Untap another target snow permanent.

Snow-Covered Island

Faerie Seer

Lava Dart

Lava Dart deals 1 damage to any target.
Flashback—Sacrifice a Mountain. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Icehide Golem

({S} can be paid with one mana from a snow source.)

Geomancer's Gambit

Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.
Draw a card.

Spell Snuff

Counter target spell.
Fateful hour — If you have 5 or less life, draw a card.

Collector Ouphe

Activated abilities of artifacts can't be activated.

Wall of Blossoms

Defender
When Wall of Blossoms enters, draw 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 Forest

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.

Wrenn and Six

+1: Return up to one target land card from your graveyard to your hand.
−1: Wrenn and Six deals 1 damage to any target.
−7: You get an emblem with "Instant and sorcery cards in your graveyard have retrace." (You may cast instant and sorcery cards from your graveyard by discarding a land card in addition to paying their other costs.)

Tribute Mage

When Tribute Mage enters, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.

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.

Shenanigans

Destroy target artifact.
Dredge 1 (If you would draw a card, you may mill a card instead. If you do, return this card from your graveyard to your hand.)

Iceberg Cancrix

Whenever another snow permanent you control enters, you may have target player mill two cards.