Jötun Owl Keeper

Bird

Cumulative upkeep {W} or {U} (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.)
When this creature dies, create a 1/1 white Bird creature token with flying for each age counter on it.

Lovisa Coldeyes

Each creature that's a Barbarian, a Warrior, or a Berserker gets +2/+2 and has haste.

Magmatic Core

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.)
At the beginning of your end step, this enchantment deals X damage divided as you choose among any number of target creatures, where X is the number of age counters on it.

Martyr of Ashes

{2}, Reveal X red cards from your hand, Sacrifice this creature: This creature deals X damage to each creature without flying.

Ohran Yeti

{2}{S}: Target snow creature gains first strike until end of turn. ({S} can be paid with one mana from a snow source.)

Orcish Bloodpainter

{T}, Sacrifice a creature: This creature deals 1 damage to any target.

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.

Rite of Flame

Add {R}{R}, then add {R} for each card named Rite of Flame in each graveyard.

Skred

Skred deals damage to target creature equal to the number of snow permanents you control.

Stalking Yeti

When this creature enters, if it's on the battlefield, it deals damage equal to its power to target creature an opponent controls and that creature deals damage equal to its power to this creature.
{2}{S}: Return this creature to its owner's hand. Activate only as a sorcery. ({S} can be paid with one mana from a snow source.)

Surging Flame

Ripple 4 (When you cast this spell, you may reveal the top four cards of your library. You may cast spells with the same name as this spell from among those cards without paying their mana costs. Put the rest on the bottom of your library.)
Surging Flame deals 2 damage to any target.

Coldsnap