Barad-dûr

Barad-dûr enters tapped unless you control a legendary creature.
{T}: Add {B}.
{X}{X}{B}, {T}: Amass Orcs X. Activate only if a creature died this turn.

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Mishra, Claimed by Gix

Whenever you attack, each opponent loses X life and you gain X life, where X is the number of attacking creatures. If Mishra, Claimed by Gix and a creature named Phyrexian Dragon Engine are attacking, and you both own and control them, exile them, then meld them into Mishra, Lost to Phyrexia. It enters tapped and attacking.

Glorybringer

Flying, haste
You may exert Glorybringer as it attacks. When you do, it deals 4 damage to target non-Dragon creature an opponent controls. (An exerted creature won't untap during your next untap step.)

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.

Forge, Neverwinter Charlatan

Menace
Ward—Sacrifice a creature.
Forge, Neverwinter Charlatan gets +2/+0 for each Treasure you control.
Whenever one or more players sacrifice one or more creatures, you create a tapped Treasure token. This ability triggers only once each turn.

Boneyard Scourge

Flying
Whenever a Dragon you control dies while Boneyard Scourge is in your graveyard, you may pay {1}{B}. If you do, return Boneyard Scourge from your graveyard to the battlefield.

Arcane Signet

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

Dragonlord's Servant

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

Mines of Moria

Mines of Moria enters tapped unless you control a legendary creature.
{T}: Add {R}.
{3}{R}, {T}, Exile three cards from your graveyard: Create two Treasure tokens.

The Balrog of Moria

Trample, haste
When The Balrog of Moria dies, you may exile it. When you do, for each opponent, exile up to one target creature that player controls.
Cycling {3}{R} ({3}{R}, Discard this card: Draw a card.)
When you cycle The Balrog of Moria, create two Treasure tokens.

Sol Ring

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.

Wake the Dragon

Create a 6/6 black and red Dragon creature token with flying, menace, and "Whenever this creature deals combat damage to a player, gain control of target artifact that player controls."
Flashback {6}{B}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

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.)

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.

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.

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.

Talisman of Indulgence

{T}: Add {C}.
{T}: Add {B} or {R}. Talisman of Indulgence deals 1 damage to you.

Junji, the Midnight Sky

Flying, menace
When Junji, the Midnight Sky dies, choose one —
• Each opponent discards two cards and loses 2 life.
• Put target non-Dragon creature card from a graveyard onto the battlefield under your control. You lose 2 life.

The Elder Dragon War

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — The Elder Dragon War deals 2 damage to each creature and each opponent.
II — Discard any number of cards, then draw that many cards.
III — Create a 4/4 red Dragon creature token with flying.

Phyrexian Dragon Engine

Double strike
When Phyrexian Dragon Engine enters from your graveyard, you may discard your hand. If you do, draw three cards.
Unearth {3}{R}{R}
(Melds with Mishra, Claimed by Gix.)

Big Score

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

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."

Unexpected Windfall

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.

Dragonspeaker Shaman

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

Sarkhan's Triumph

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

Takenuma, Abandoned Mire

{T}: Add {B}.
Channel — {3}{B}, Discard Takenuma, Abandoned Mire: Mill three cards, then return a creature or planeswalker card from your graveyard to your hand. This ability costs {1} less to activate for each legendary creature you control.

Bladewing the Risen

Flying
When Bladewing the Risen enters, you may return target Dragon permanent card from your graveyard to the battlefield.
{B}{R}: Dragon creatures get +1/+1 until end of turn.

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.

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."

Command Tower

Swashbuckler Extraordinaire

When Swashbuckler Extraordinaire enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Whenever you attack, you may sacrifice one or more Treasures. When you do, up to that many target creatures gain double strike until end of turn.

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.

Moria Scavenger

Deathtouch, haste
{T}, Discard a card: Draw a card. If the discarded card was a creature card, amass Orcs 1. (Put a +1/+1 counter on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Bitter Reunion

When Bitter Reunion enters, you may discard a card. If you do, draw two cards.
{1}, Sacrifice Bitter Reunion: Creatures you control gain haste until end of turn.

Zirilan of the Claw

{1}{R}{R}, {T}: Search your library for a Dragon permanent card, put that card onto the battlefield, then shuffle. That Dragon gains haste until end of turn. Exile it at the beginning of the next end step.

Rakdos Signet

Carnelian Orb of Dragonkind

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

Bonders' Enclave

{T}: Add {C}.
{3}, {T}: Draw a card. Activate only if you control a creature with power 4 or greater.

Rivaz of the Claw

Menace
{T}: Add two mana in any combination of colors. Spend this mana only to cast Dragon creature spells.
Once during each of your turns, you may cast a Dragon creature spell from your graveyard.
Whenever you cast a Dragon creature spell from your graveyard, it gains "When this creature dies, exile it."

Sarkhan, Fireblood

+1: You may discard a card. If you do, draw a card.
+1: Add two mana in any combination of colors. Spend this mana only to cast Dragon spells.
−7: Create four 5/5 red Dragon creature tokens with flying.

Cursed Mirror

{T}: Add {R}.
As Cursed Mirror enters, you may have it become a copy of any creature on the battlefield until end of turn, except it has haste.

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.

Gadrak, the Crown-Scourge

Flying
Gadrak, the Crown-Scourge can't attack unless you control four or more artifacts.
At the beginning of your end step, create a Treasure token for each nontoken creature that died this turn. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Utvara Hellkite

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

Bladewing's Thrall

Bladewing's Thrall has flying as long as you control a Dragon.
When a Dragon enters, you may return Bladewing's Thrall from your graveyard to the battlefield.