Thrakkus the Butcher

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

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.

Rite of Replication

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

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.

Brudiclad, Telchor Engineer

Creature tokens you control have haste.
At the beginning of combat on your turn, create a 2/1 blue Phyrexian Myr artifact creature token. Then you may choose a token you control. If you do, each other token you control becomes a copy of that token.

Forest

Command Tower

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

Rootbound Crag

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

Nature's Lore

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

Hinterland Harbor

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

Reliquary Tower

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

Spark Double

You may have Spark Double enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Dragonspeaker Shaman

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

Balefire Dragon

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

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.

Arcane Signet

Draconic Muralists

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

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.

Keiga, the Tide Star

Flying
When Keiga, the Tide Star dies, gain control of target creature.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Traverse the Outlands

Search your library for up to X basic land cards, where X is the greatest power among creatures you control. Put those cards onto the battlefield tapped, then shuffle.

Frontier Bivouac

Frontier Bivouac enters tapped.
{T}: Add {G}, {U}, or {R}.

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.

Ryusei, the Falling Star

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

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.)

Atarka, World Render

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

Hellkite Charger

Flying, haste
Whenever Hellkite Charger attacks, you may pay {5}{R}{R}. If you do, untap all attacking creatures and after this phase, there is an additional combat phase.

Sulfur Falls

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

Psionic Pulse

Counter target noncreature spell. (Then exile this card. You may cast the creature later from exile.)

Sapphire Dragon

Flying
Whenever Sapphire Dragon attacks or blocks, scry 2.

Sapphire Dragon // Psionic Pulse

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.

Island

Double Major

Copy target creature spell you control, except it isn't legendary if the spell is legendary. (A copy of a creature spell becomes a token.)

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.

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.

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Mirror Box

The "legend rule" doesn't apply to permanents you control.
Each legendary creature you control gets +1/+1.
Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

Rockfall Vale

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

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.

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.

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Mountain

Beast Within

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

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.)

Training Center

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

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Prismatic Vista

{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Rejuvenating Springs

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

Ketria Triome

({T}: Add {G}, {U}, or {R}.)
Ketria Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Irenicus's Vile Duplication

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.

Breeding Pool

({T}: Add {G} or {U}.)
As Breeding Pool enters, you may pay 2 life. If you don't, it enters tapped.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Dragonborn Champion

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

Stomping Ground

({T}: Add {R} or {G}.)
As Stomping Ground enters, you may pay 2 life. If you don't, it enters tapped.

Simic Signet

Izzet Signet

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

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.

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.

Utvara Hellkite

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

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.)

Spire Garden

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

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.

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

Minion of the Mighty

Menace
Pack tactics — Whenever Minion of the Mighty attacks, if you attacked with creatures with total power 6 or greater this combat, you may put a Dragon creature card from your hand onto the battlefield tapped and attacking.

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.

Kindred Discovery

As Kindred Discovery enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

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.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

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.

Scaled Nurturer

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

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.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Three Visits

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

Ghostly Flicker

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

Gruul Signet

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.

Lightning Greaves

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

Farseek

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

Sol Ring

Iymrith, Desert Doom

Flying
Iymrith, Desert Doom has ward {4} as long as it's untapped.
Whenever Iymrith deals combat damage to a player, draw a card. Then if you have fewer than three cards in hand, draw cards equal to the difference.

Zoological Study

Mill five cards, then return a creature card milled this way to your hand. (Then exile this card. You may cast the artifact later from exile.)

Monster Manual

{1}{G}, {T}: You may put a creature card from your hand onto the battlefield.

Monster Manual // Zoological Study

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.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

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.