Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Play with Fire

Play with Fire deals 2 damage to any target. If a player is dealt damage this way, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Darksteel Citadel

End the Festivities

End the Festivities deals 1 damage to each opponent and each creature and planeswalker they control.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Jaya's Immolating Inferno

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Jaya's Immolating Inferno deals X damage to each of up to three targets.

Mountain

Seize the Spoils

As an additional cost to cast this spell, discard a card.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Blaze

Spore Frog

Sacrifice Spore Frog: Prevent all combat damage that would be dealt this turn.

Shock

Prevent all combat damage that would be dealt this turn.

Wastes

Lightning Bolt

Lightning Bolt deals 3 damage to any target.