Have

Dragonspeaker Shaman

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

Dragon Egg

Defender
When Dragon Egg dies, create a 2/2 red Dragon creature token with flying and "{R}: This creature gets +1/+0 until end of turn."

Dragons

Lathliss, Dragon Queen

Flying
Whenever another nontoken Dragon you control enters, create a 5/5 red Dragon creature token with flying.
{1}{R}: Dragons you control get +1/+0 until end of turn.

Bogardan Dragonheart

Sacrifice another creature: Until end of turn, Bogardan Dragonheart becomes a Dragon with base power and toughness 4/4, flying, and haste.

Sarkhan's Whelp

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever you activate an ability of a Sarkhan planeswalker, Sarkhan's Whelp deals 1 damage to any target.

Thriving Bluff

Thriving Bluff enters tapped. As it enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Furnace Whelp

Flying
{R}: Furnace Whelp gets +1/+0 until end of turn.

Mountain

Sarkhan's Rage

Sarkhan's Rage deals 5 damage to any target. If you control no Dragons, Sarkhan's Rage deals 2 damage to you.

Scorching Dragonfire

Scorching Dragonfire deals 3 damage to target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.

Dragon Fodder

Create two 1/1 red Goblin creature tokens.

Dragon's Hoard

Whenever a Dragon you control enters, put a gold counter on Dragon's Hoard.
{T}, Remove a gold counter from Dragon's Hoard: Draw a card.
{T}: Add one mana of any color.

Kargan Dragonrider

As long as you control a Dragon, this creature has flying.

Dragon Mage

Flying
Whenever this creature deals combat damage to a player, each player discards their hand, then draws seven cards.

Plundering Predator

Flying
When Plundering Predator enters, you may discard a card. If you do, draw a card.

Dragonlord's Servant

Dragon spells you cast cost {1} less to cast.

Sparktongue Dragon

Flying
When Sparktongue Dragon enters, you may pay {2}{R}. When you do, it deals 3 damage to any target.

Tormenting Voice

As an additional cost to cast this spell, discard a card.
Draw two cards.

Sarkhan, the Dragonspeaker

+1: Until end of turn, Sarkhan, the Dragonspeaker becomes a legendary 4/4 red Dragon creature with flying, indestructible, and haste. (He doesn't lose loyalty while he's not a planeswalker.)
−3: Sarkhan, the Dragonspeaker deals 4 damage to target creature.
−6: You get an emblem with "At the beginning of your draw step, draw two additional cards" and "At the beginning of your end step, discard your hand."