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.

Fires of Yavimaya

Creatures you control have haste.
Sacrifice Fires of Yavimaya: Target creature gets +2/+2 until end of turn.

Vandalblast

Destroy target artifact you don't control.
Overload {4}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Klauth, Unrivaled Ancient

Flying, haste
Whenever Klauth, Unrivaled Ancient attacks, add X mana in any combination of colors, where X is the total power of attacking creatures. Spend this mana only to cast spells. Until end of turn, you don't lose this mana as steps and phases end.

Harmonize

Scaled Nurturer

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

Secluded Courtyard

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

Atarka, World Render

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

Acolyte of Bahamut

Commander creatures you own have "The first Dragon spell you cast each turn costs {2} less to cast."

Draconic Muralists

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

Crucible of Fire

Goldspan Dragon

Flying, haste
Whenever Goldspan Dragon attacks or becomes the target of a spell, create a Treasure token.
Treasures you control have "{T}, Sacrifice this artifact: Add two mana of any one color."

Sarkhan's Triumph

Search your library for a Dragon creature card, reveal it, put it into your hand, then shuffle.

Thrakkus the Butcher

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

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Bootleggers' Stash

Lands you control have "{T}: Create a Treasure token."

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.

Sol Ring

Last March of the Ents

This spell can't be countered.
Draw cards equal to the greatest toughness among creatures you control, then put any number of creature cards from your hand onto the battlefield.

Dragonmaster Outcast

At the beginning of your upkeep, if you control six or more lands, create a 5/5 red Dragon creature token with flying.

Dragon Tempest

Whenever a creature you control with flying enters, it gains haste until end of turn.
Whenever a Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.

Jade Orb of Dragonkind

{T}: Add {G}. When you spend this mana to cast a Dragon creature spell, it enters with an additional +1/+1 counter on it and gains hexproof until your next turn. (It can't be the target of spells or abilities your opponents control.)

Gruul Turf

Gruul Turf enters tapped.
When Gruul Turf enters, return a land you control to its owner's hand.
{T}: Add {R}{G}.

Patron of the Arts

When Patron of the Arts enters or dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Hunter's Insight

Choose target creature you control. Whenever that creature deals combat damage to a player or planeswalker this turn, draw that many cards.

Wrathful Red Dragon

Flying
Whenever a Dragon you control is dealt damage, it deals that much damage to any target that isn't a Dragon.

Klauth's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Breathe Flame — Klauth's Will deals X damage to each creature without flying.
• Smash Relics — Destroy up to X target artifacts and/or enchantments.

Mountain

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Moss Diamond

Moss Diamond enters tapped.
{T}: Add {G}.

Roaming Throne

Ward {2}
As Roaming Throne enters, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

There and Back Again

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Up to one target creature can't block for as long as you control There and Back Again. The Ring tempts you.
II — Search your library for a Mountain card, put it onto the battlefield, then shuffle.
III — Create Smaug, a legendary 6/6 red Dragon creature token with flying, haste, and "When this creature dies, create fourteen Treasure tokens."

Forest

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Temple of the Dragon Queen

As Temple of the Dragon Queen enters, you may reveal a Dragon card from your hand. Temple of the Dragon Queen enters tapped unless you revealed a Dragon card this way or you control a Dragon.
As Temple of the Dragon Queen enters, choose a color.
{T}: Add one mana of the chosen color.

Atarka Monument

{T}: Add {R} or {G}.
{4}{R}{G}: Atarka Monument becomes a 4/4 red and green Dragon artifact creature with flying until end of turn.

Ganax, Astral Hunter

Flying
Whenever Ganax, Astral Hunter or another Dragon you control enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Choose a Background (You can have a Background as a second commander.)

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Explore

You may play an additional land this turn.
Draw a card.

Drakuseth, Maw of Flames

Flying
Whenever Drakuseth attacks, it deals 4 damage to any target and 3 damage to each of up to two other targets.

Decimate

Destroy target artifact, target creature, target enchantment, and target land. (You can't cast this spell unless you have legal choices for all its targets.)

Dragonspeaker Shaman

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

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Colossal Majesty

At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.

Ryusei, the Falling Star

Flying
When Ryusei, the Falling Star dies, it deals 5 damage to each creature without flying.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Spit Flame

Spit Flame deals 4 damage to target creature.
Whenever a Dragon you control enters, you may pay {R}. If you do, return Spit Flame from your graveyard to your hand.

Dragonlord's Servant

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

Incinerator of the Guilty

Flying, trample
Whenever Incinerator of the Guilty deals combat damage to a player, you may collect evidence X. When you do, Incinerator of the Guilty deals X damage to each creature and planeswalker that player controls. (To collect evidence X, exile cards with total mana value X or greater from your graveyard.)

Up the Beanstalk

When Up the Beanstalk enters and whenever you cast a spell with mana value 5 or greater, draw a card.

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Return of the Wildspeaker

Choose one —
• Draw cards equal to the greatest power among non-Human creatures you control.
• Non-Human creatures you control get +3/+3 until end of turn.

Ancient Bronze Dragon

Flying
Whenever Ancient Bronze Dragon deals combat damage to a player, roll a d20. When you do, put X +1/+1 counters on each of up to two target creatures, where X is the result.

Haven of the Spirit Dragon

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a Dragon creature spell.
{2}, {T}, Sacrifice Haven of the Spirit Dragon: Return target Dragon creature card or Ugin planeswalker card from your graveyard to your hand.

Demand Answers

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

Breath Weapon

Breath Weapon deals 2 damage to each non-Dragon creature.

Gruul Signet

Urza's Incubator

As Urza's Incubator enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Elemental Bond

Whenever a creature you control with power 3 or greater enters, draw a card.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Command Tower

Unclaimed Territory

As Unclaimed Territory enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

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.

Carnelian Orb of Dragonkind

{T}: Add {R}. If that mana is spent on a Dragon creature spell, it gains haste until end of turn.

Goblin Anarchomancer

Each spell you cast that's red or green costs {1} less to cast.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.