Urza's Filter

Multicolored spells cost {2} less to cast.

Chandra's Incinerator

This spell costs {X} less to cast, where X is the total amount of noncombat damage dealt to your opponents this turn.
Trample
Whenever a source you control deals noncombat damage to an opponent, this creature deals that much damage to target creature or planeswalker that player controls.

Tokka & Rahzar, Terrible Twos

This spell can't be countered.
Menace
Whenever a player casts a spell, if the amount of mana spent to cast it was less than its mana value, Tokka & Rahzar deal 3 damage to that player.

Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)