Star of Extinction

Destroy target land. Star of Extinction deals 20 damage to each creature and each planeswalker.

Boros Reckoner

Whenever Boros Reckoner is dealt damage, it deals that much damage to any target.
{R/W}: Boros Reckoner gains first strike until end of turn.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Gift of Immortality

Enchant creature
When enchanted creature dies, return that card to the battlefield under its owner's control. Return Gift of Immortality to the battlefield attached to that creature at the beginning of the next end step.

Plains

Spiteful Sliver

Sliver creatures you control have "Whenever this creature is dealt damage, it deals that much damage to target player or planeswalker."

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Marauding Raptor

Creature spells you cast cost {1} less to cast.
Whenever another creature you control enters, Marauding Raptor deals 2 damage to it. If a Dinosaur is dealt damage this way, Marauding Raptor gets +2/+0 until end of turn.

Deflecting Palm

The next time a source of your choice would deal damage to you this turn, prevent that damage. If damage is prevented this way, Deflecting Palm deals that much damage to that source's controller.

Mountain

Pride Guardian

Defender
Whenever Pride Guardian blocks, you gain 3 life.

Lightning Helix

Lightning Helix deals 3 damage to any target and you gain 3 life.

Spitemare

Whenever Spitemare is dealt damage, it deals that much damage to any target.