Miirym, Sentinel Wyrm

Flying, ward {2}
Whenever another nontoken Dragon you control enters, create a token that's a copy of it, except the token isn't legendary.

Echoing Assault

Creature tokens you control have menace.
Whenever you attack a player, choose target nontoken creature that's attacking that player. Create a token that's a copy of that creature, except it's 1/1. The token enters tapped and attacking that player. Sacrifice it at the beginning of the next end step.

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.

Herald's Horn

As Herald's Horn enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Utvara Hellkite

Flying
Whenever a Dragon you control attacks, create a 6/6 red Dragon creature token with flying.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Forest

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Dragonborn Champion

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

Korlessa, Scale Singer

You may look at the top card of your library any time.
You may cast Dragon spells from the top of your library.

Atarka, World Render

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

Spire Garden

Spire Garden enters tapped unless you have two or more opponents.
{T}: Add {R} or {G}.

Scaled Nurturer

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

Stormcarved Coast

Stormcarved Coast enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.

Rockfall Vale

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

Renari, Merchant of Marvels

You may cast Dragon spells and artifact spells as though they had flash.
Choose a Background (You can have a Background as a second commander.)

Rootbound Crag

Rootbound Crag enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Command Tower

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

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.

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Hinterland Harbor

Hinterland Harbor enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Cultivate

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.

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."

Carnelian Orb of Dragonkind

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

Cinder Glade

({T}: Add {R} or {G}.)
Cinder Glade enters tapped unless you control two or more basic lands.

Thrakkus the Butcher

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

Dragonspeaker Shaman

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

Mountain

Astral Dragon

Flying
Project Image — When Astral Dragon enters, create two tokens that are copies of target noncreature permanent, except they're 3/3 Dragon creatures in addition to their other types, and they have flying.

Dragonlord's Servant

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

Ancient Silver Dragon

Flying
Whenever Ancient Silver Dragon deals combat damage to a player, roll a d20. Draw cards equal to the result. You have no maximum hand size for the rest of the game.

Garruk's Uprising

When Garruk's Uprising enters, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample.
Whenever a creature you control with power 4 or greater enters, draw a card.

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.

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.

Acolyte of Bahamut

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

Orb of Dragonkind

{1}, {T}: Add two mana in any combination of colors. Spend this mana only to cast Dragon spells or activate abilities of Dragons.
{R}, {T}, Sacrifice Orb of Dragonkind: Look at the top seven cards of your library. You may reveal a Dragon card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Kodama's Reach

Rejuvenating Springs

Rejuvenating Springs enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

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.

Scourge of Valkas

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

Arcane Signet

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.

Crucible of Fire

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

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.)

Sol Ring

Lapis Orb of Dragonkind

{T}: Add {U}. When you spend this mana to cast a Dragon creature spell, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Sarkhan, Soul Aflame

Dragon spells you cast cost {1} less to cast.
Whenever a Dragon you control enters, you may have Sarkhan, Soul Aflame become a copy of it until end of turn, except its name is Sarkhan, Soul Aflame and it's legendary in addition to its other types.

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)

Lozhan, Dragons' Legacy

Flying
Whenever you cast an Adventure or Dragon spell, Lozhan, Dragons' Legacy deals damage equal to that spell's mana value to any target that isn't a commander.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Atsushi, the Blazing Sky

Flying, trample
When Atsushi, the Blazing Sky dies, choose one —
• Exile the top two cards of your library. Until the end of your next turn, you may play those cards.
• Create three Treasure tokens.

Terror of the Peaks

Flying
Spells your opponents cast that target Terror of the Peaks cost an additional 3 life to cast.
Whenever another creature you control enters, Terror of the Peaks deals damage equal to that creature's power to any target.

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Island

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.

Training Center

Training Center enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Genesis Ultimatum

Look at the top five cards of your library. Put any number of permanent cards from among them onto the battlefield and the rest into your hand. Exile Genesis Ultimatum.

Cavern-Hoard Dragon

This spell costs {X} less to cast, where X is the greatest number of artifacts an opponent controls.
Flying, trample, haste
Whenever Cavern-Hoard Dragon deals combat damage to a player, you create a Treasure token for each artifact that player controls.

Skyline Despot

Flying
When Skyline Despot 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.

Lightning Greaves

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

Rampant Growth

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

Shadow in the Warp

The first creature spell you cast each turn costs {2} less to cast.
Whenever an opponent casts their first noncreature spell each turn, Shadow in the Warp deals 2 damage to that player.

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.)

Balefire Dragon

Flying
Whenever Balefire Dragon deals combat damage to a player, it deals that much damage to each creature that player controls.

Counterspell

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.

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.

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.

Drakuseth, Maw of Flames

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

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.)

Heroic Intervention

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

Draconic Muralists

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

Ryusei, the Falling Star

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

Goblin Anarchomancer

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

Rishkar's Expertise

Draw cards equal to the greatest power among creatures you control.
You may cast a spell with mana value 5 or less from your hand without paying its mana cost.

Dreamroot Cascade

Dreamroot Cascade enters tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

Reliquary 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.