Blazing Volley

Blazing Volley deals 1 damage to each creature your opponents control.

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Barrage of Boulders

Barrage of Boulders deals 1 damage to each creature you don't control.
Ferocious — If you control a creature with power 4 or greater, creatures can't block this turn.

Boiling Earth

Boiling Earth deals 1 damage to each creature your opponents control.
Awaken 4—{6}{R} (If you cast this spell for {6}{R}, also put four +1/+1 counters on target land you control and it becomes a 0/0 Elemental creature with haste. It's still a land.)

Burning Earth

Whenever a player taps a nonbasic land for mana, this enchantment deals 1 damage to that player.

Ghyrson Starn, Kelermorph

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Three Autostubs — Whenever another source you control deals exactly 1 damage to a permanent or player, Ghyrson Starn deals 2 damage to that permanent or player.

Ophidian Eye

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Tandem Lookout

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Tandem Lookout is paired with another creature, each of those creatures has "Whenever this creature deals damage to an opponent, draw a card."