Lotus Petal

{T}, Sacrifice this artifact: Add one mana of any color.

Shock

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

Skewer the Critics

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Skewer the Critics deals 3 damage to any target.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Strangle

Strangle deals 3 damage to target creature or planeswalker.

Mountain

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Seal of Fire

Sacrifice this enchantment: It deals 2 damage to any target.

Seething Song

Mishra's Bauble

{T}, Sacrifice this artifact: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Eidolon of the Great Revel

Whenever a player casts a spell with mana value 3 or less, this creature deals 2 damage to that player.