Mana Leak

Counter target spell unless its controller pays {3}.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Kjeldoran War Cry

Creatures you control get +X/+X until end of turn, where X is 1 plus the number of cards named Kjeldoran War Cry in all graveyards.

Trumpet Blast

Attacking creatures get +2/+0 until end of turn.

Seeker of the Way

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, Seeker of the Way gains lifelink until end of turn.

Snow-Covered Plains

Snow-Covered Mountain

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Jeskai Elder

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Jeskai Elder deals combat damage to a player, you may draw a card. If you do, discard a card.

Monastery Swiftspear

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Volatile Fjord

({T}: Add {U} or {R}.)
Volatile Fjord enters tapped.

Skred

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

Nivix Cyclops

Defender
Whenever you cast an instant or sorcery spell, Nivix Cyclops gets +3/+0 until end of turn and can attack this turn as though it didn't have defender.

Aether Spellbomb

{U}, Sacrifice Aether Spellbomb: Return target creature to its owner's hand.
{1}, Sacrifice Aether Spellbomb: Draw a card.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Alpine Meadow

({T}: Add {R} or {W}.)
Alpine Meadow enters tapped.

Glacial Floodplain

({T}: Add {W} or {U}.)
Glacial Floodplain enters tapped.

Electrickery

Electrickery deals 1 damage to target creature you don't control.
Overload {1}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Pyrite Spellbomb

{R}, Sacrifice Pyrite Spellbomb: It deals 2 damage to any target.
{1}, Sacrifice Pyrite Spellbomb: Draw a card.

Dwarven Forge-Chanter

Ward—Pay 2 life. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays 2 life.)
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Bloodwater Entity

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Bloodwater Entity enters, you may put target instant or sorcery card from your graveyard on top of your library.

Snow-Covered Island

Rush of Adrenaline

Target creature gets +2/+1 and gains trample until end of turn.

Sunbeam Spellbomb

{W}, Sacrifice Sunbeam Spellbomb: You gain 5 life.
{1}, Sacrifice Sunbeam Spellbomb: Draw a card.