Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Thunderbreak Regent

Flying
Whenever a Dragon you control becomes the target of a spell or ability an opponent controls, Thunderbreak Regent deals 3 damage to that player.

Stormbreath Dragon

Flying, haste, protection from white
{5}{R}{R}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
When Stormbreath Dragon becomes monstrous, it deals damage to each opponent equal to the number of cards in that player's hand.

Crucible of Fire

Atarka, World Render

Flying, trample
Whenever a Dragon you control attacks, it gains double strike until end of turn.

Sarkhan, Fireblood

+1: You may discard a card. If you do, draw a card.
+1: Add two mana in any combination of colors. Spend this mana only to cast Dragon spells.
−7: Create four 5/5 red Dragon creature tokens with flying.

Dragonspeaker Shaman

Dragon spells you cast cost {2} less to cast.

Sarkhan Unbroken

+1: Draw a card, then add one mana of any color.
−2: Create a 4/4 red Dragon creature token with flying.
−8: Search your library for any number of Dragon creature cards, put them onto the battlefield, then shuffle.