Allosaurus Rider

You may exile two green cards from your hand rather than pay this spell's mana cost.
Allosaurus Rider's power and toughness are each equal to 1 plus the number of lands you control.

Snow-Covered Forest

Lightning Storm

Lightning Storm deals X damage to any target, where X is 3 plus the number of charge counters on Lightning Storm.
Discard a land card: Put two charge counters on Lightning Storm. You may choose a new target for it. Any player may activate this ability but only if Lightning Storm is on the stack.

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.

Balduvian Rage

Target attacking creature gets +X/+0 until end of turn.
Draw a card at the beginning of the next turn's upkeep.

Skred

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

Rimehorn Aurochs

Trample
Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.
{2}{S}: Target creature blocks target creature this turn if able. ({S} can be paid with one mana from a snow source.)

Snow-Covered Mountain

Boreal Druid

Bull Aurochs

Trample
Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.

Into the North

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

Aurochs Herd

Trample
When this creature enters, you may search your library for an Aurochs card, reveal it, put it into your hand, then shuffle.
Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.