Ambitious Dragonborn

This creature enters with X +1/+1 counters on it, where X is the greatest power among creatures you control and creature cards in your graveyard.

Inferno of the Star Mounts

This spell can't be countered.
Flying, haste
{R}: Inferno of the Star Mounts gets +1/+0 until end of turn. When its power becomes 20 this way, it deals 20 damage to any target.

Destructor Dragon

Flying
When this creature dies, destroy target noncreature permanent.

Scourge of Valkas

Flying
Whenever this creature or another Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.
{R}: This creature gets +1/+0 until end of turn.

Vrondiss, Rage of Ancients

Enrage — Whenever Vrondiss is dealt damage, you may create a 5/4 red and green Dragon Spirit creature token with "When this token deals damage, sacrifice it."
Whenever you roll one or more dice, you may have Vrondiss deal 1 damage to itself.

Thrakkus the Butcher

Trample
Whenever Thrakkus attacks, double the power of each Dragon you control until end of turn.

Jugan, the Rising Star

Flying
When Jugan dies, you may distribute five +1/+1 counters among any number of target creatures.

Thunderbreak Regent

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

Scaled Nurturer

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

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.

Llanowar Elves

Arni Slays the Troll

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Target creature you control fights up to one target creature you don't control.
II — Add {R}. Put two +1/+1 counters on up to one target creature you control.
III — You gain life equal to the greatest power among creatures you control.

Llanowar Tribe

Siege Dragon

Flying
When this creature enters, destroy all Walls your opponents control.
Whenever this creature attacks, if defending player controls no Walls, it deals 2 damage to each creature without flying that player controls.

Livaan, Cultist of Tiamat

Whenever you cast a noncreature spell, target creature gets +X/+0 until end of turn, where X is that spell's mana value.
Choose a Background (You can have a Background as a second commander.)

Explosive Crystal

Explosive Crystal deals 4 damage divided as you choose among any number of targets. (Then exile this card. You may cast the creature later from exile.)

Amethyst Dragon

Amethyst Dragon // Explosive Crystal

Mana-Charged Dragon

Flying, trample
Join forces — Whenever this creature attacks or blocks, each player starting with you may pay any amount of mana. This creature gets +X/+0 until end of turn, where X is the total amount of mana paid this way.

Savage Ventmaw

Flying
Whenever this creature attacks, add {R}{R}{R}{G}{G}{G}. Until end of turn, you don't lose this mana as steps and phases end.

Flameblast Dragon

Flying
Whenever this creature attacks, you may pay {X}{R}. If you do, it deals X damage to any target.

Draconic Muralists

When this creature dies, you may search your library for a Dragon card, reveal it, put it into your hand, then shuffle.

Dragonborn Champion

Trample
Whenever a source you control deals 5 or more damage to a player, draw a card.

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

This creature can't be blocked by creatures with power 3 or less.

Dread Linnorm // Scale Deflection

Draconic Disciple

{T}: Add one mana of any color.
{7}, {T}, Sacrifice this creature: Create a 5/5 red Dragon creature token with flying.

Manaform Hellkite

Flying
Whenever you cast a noncreature spell, create an X/X red Dragon Illusion creature token with flying and haste, where X is the amount of mana spent to cast that spell. Exile that token at the beginning of the next end step.

Bogardan Hellkite

Flash
Flying
When this creature enters, it deals 5 damage divided as you choose among any number of targets.

Llanowar Reborn

This land enters tapped.
{T}: Add {G}.
Graft 1 (This land enters with a +1/+1 counter on it. Whenever a creature enters, you may move a +1/+1 counter from this land onto it.)

Rapacious Dragon

Flying
When this creature enters, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Herdchaser Dragon

Flying, trample
Megamorph {5}{G}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When this creature is turned face up, put a +1/+1 counter on each other Dragon creature you control.

Radha, Heir to Keld

Whenever Radha attacks, you may add {R}{R}.
{T}: Add {G}.

Skyline Despot

Flying
When this creature enters, you become the monarch.
At the beginning of your upkeep, if you're the monarch, create a 5/5 red Dragon creature token with flying.

Atarka, World Render

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

Llanowar Visionary

When this creature enters, draw a card.
{T}: Add {G}.

Dissonant Wave

Counter target activated or triggered ability from a noncreature source. (Then exile this card. You may cast the creature later from exile.)

Emerald Dragon

Emerald Dragon // Dissonant Wave

Forktail Sweep

Forktail Sweep deals 1 damage to each creature you don't control. (Then exile this card. You may cast the creature later from exile.)

Fang Dragon

Fang Dragon // Forktail Sweep

Remnant of the Rising Star

Flying
Whenever another creature you control enters, you may pay {X}. When you do, put X +1/+1 counters on that creature.
As long as you control five or more modified creatures, this creature gets +5/+5 and has trample. (Equipment, Auras you control, and counters are modifications.)

Jugan Defends the Temple

(As this Saga enters and after your draw step, add a lore counter.)
I — Create a 1/1 green Human Monk creature token with "{T}: Add {G}."
II — Put a +1/+1 counter on each of up to two target creatures.
III — Exile this Saga, then return it to the battlefield transformed under your control.