Ashmouth Dragon

Flying
Whenever you cast an instant or sorcery spell, Ashmouth Dragon deals 2 damage to any target.

Smoldering Egg

Defender
Whenever you cast an instant or sorcery spell, put a number of ember counters on Smoldering Egg equal to the amount of mana spent to cast that spell. Then if Smoldering Egg has seven or more ember counters on it, remove them and transform Smoldering Egg.

Smoldering Egg // Ashmouth Dragon

Dragon Tyrant

Flying, trample
Double strike (This creature deals both first-strike and regular combat damage.)
At the beginning of your upkeep, sacrifice Dragon Tyrant unless you pay {R}{R}{R}{R}.
{R}: Dragon Tyrant gets +1/+0 until end of turn.

Scaled Nurturer

{T}: Add {G}. When you spend this mana to cast a Dragon creature spell, you gain 2 life.

Slumbering Dragon

Flying
Slumbering Dragon can't attack or block unless it has five or more +1/+1 counters on it.
Whenever a creature attacks you or a planeswalker you control, put a +1/+1 counter on Slumbering Dragon.

Temple of Abandon

Temple of Abandon enters tapped.
When Temple of Abandon enters, scry 1.
{T}: Add {R} or {G}.

Mountain

Llanowar Elves

Imperial Hellkite

Flying
Morph {6}{R}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Imperial Hellkite is turned face up, you may search your library for a Dragon card, reveal it, put it into your hand, then shuffle.

Rockfall Vale

Rockfall Vale enters tapped unless you control two or more other lands.
{T}: Add {R} or {G}.

Forest

Scale Deflection

Put two +1/+1 counters on target creature and untap it. It gains hexproof until end of turn. (Then exile this card. You may cast the creature later from exile.)

Dread Linnorm

Dread Linnorm can't be blocked by creatures with power 3 or less.

Dread Linnorm // Scale Deflection

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Shivan Devastator

Flying, haste
Shivan Devastator enters with X +1/+1 counters on it.

Timbercrown Pathway

Cragcrown Pathway

Cragcrown Pathway // Timbercrown Pathway

Dragonspeaker Shaman

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

Dragonlord Atarka

Flying, trample
When Dragonlord Atarka enters, it deals 5 damage divided as you choose among any number of target creatures and/or planeswalkers your opponents control.

Reckless Barbarian

Sacrifice Reckless Barbarian: Add {R}{R}.

Atarka, World Render

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

Copperline Gorge

Copperline Gorge enters tapped unless you control two or fewer other lands.
{T}: Add {R} or {G}.

Earthquake Dragon

This spell costs {X} less to cast, where X is the total mana value of Dragons you control.
Flying, trample
{2}{G}, Sacrifice a land: Return Earthquake Dragon from your graveyard to your hand.