Leyline of Mutation

If Leyline of Mutation is in your opening hand, you may begin the game with it on the battlefield.
You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast.

Mosswort Bridge

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Mosswort Bridge enters tapped.
{T}: Add {G}.
{G}, {T}: You may play the exiled card without paying its mana cost if creatures you control have total power 10 or greater.

Firemind Vessel

Firemind Vessel enters tapped.
{T}: Add two mana of different colors.

Draconic Muralists

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

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.

Sol Ring

Season of the Bold

Choose up to five {P} worth of modes. You may choose the same mode more than once.
{P} — Create a tapped Treasure token.
{P}{P} — Exile the top two cards of your library. Until the end of your next turn, you may play them.
{P}{P}{P} — Until the end of your next turn, whenever you cast a spell, Season of the Bold deals 2 damage to up to one target creature.

Lurking Green Dragon

Flying
Lurking Green Dragon can't attack unless defending player controls a creature with flying.

Spectator Seating

Spectator Seating enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

Blazemire Verge

{T}: Add {B}.
{T}: Add {R}. Activate only if you control a Swamp or a Mountain.

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.")

Hoard-Smelter Dragon

Flying
{3}{R}: Destroy target artifact. Hoard-Smelter Dragon gets +X/+0 until end of turn, where X is that artifact's mana value.

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.

Knollspine Dragon

Flying
When Knollspine Dragon enters, you may discard your hand and draw cards equal to the damage dealt to target opponent this turn.

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.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Sapphire Medallion

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

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

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.")

Gilded Lotus

Sunscorch Regent

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on Sunscorch Regent and you gain 1 life.

Island

Leyline Tyrant

Flying
You don't lose unspent red mana as steps and phases end.
When Leyline Tyrant dies, you may pay any amount of {R}. When you do, it deals that much damage to any target.

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.)

Dragonlord Ojutai

Flying
Dragonlord Ojutai has hexproof as long as it's untapped.
Whenever Dragonlord Ojutai deals combat damage to a player, look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Forest

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.

Blue Dragon

Flying
Lightning Breath — When Blue Dragon enters, until your next turn, target creature an opponent controls gets -3/-0, up to one other target creature gets -2/-0, and up to one other target creature gets -1/-0.

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.

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.

Sailors' Bane

This spell costs {1} less to cast for each card you own in exile and in your graveyard that's an instant card, a sorcery card, or a card that has an Adventure.
Ward {4} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}.)

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.

Morphic Pool

Morphic Pool enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Uncharted Haven

This land enters tapped. As it enters, choose a color.
{T}: Add one mana of the chosen color.

Exotic Orchard

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

Dragon's Approach

Dragon's Approach deals 3 damage to each opponent. You may exile Dragon's Approach and four cards named Dragon's Approach from your graveyard. If you do, search your library for a Dragon creature card, put it onto the battlefield, then shuffle.
A deck can have any number of cards named Dragon's Approach.

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

Dread Linnorm can't be blocked by creatures with power 3 or less.

Dread Linnorm // Scale Deflection

Command Tower

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

Tiamat

Flying
When Tiamat enters, if you cast it, search your library for up to five Dragon cards not named Tiamat that each have different names, reveal them, put them into your hand, then shuffle.

Skanos Dragonheart

Whenever Skanos Dragonheart attacks, it gets +X/+X until end of turn, where X is the greatest power among other Dragons you control and Dragon cards in your graveyard.
Choose a Background (You can have a Background as a second commander.)

Carnelian Orb of Dragonkind

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

Fellwar Stone

Sea Gate

Sea Gate enters tapped.
As Sea Gate enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

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.)

Reckless Barbarian

Sacrifice Reckless Barbarian: Add {R}{R}.

Bathe in Gold

Create a Treasure token. (Then exile this card. You may cast the creature later from exile.)

Young Red Dragon

Young Red Dragon // Bathe in Gold

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.)

Arcane Signet

Hellkite Igniter

Flying, haste
{1}{R}: Hellkite Igniter gets +X/+0 until end of turn, where X is the number of artifacts you control.

Manor Gate

Manor Gate enters tapped.
As Manor Gate enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

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.)

Hall of Storm Giants

If you control two or more other lands, Hall of Storm Giants enters tapped.
{T}: Add {U}.
{5}{U}: Until end of turn, Hall of Storm Giants becomes a 7/7 blue Giant creature with ward {3}. It's still a land. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)

Sand Augury

Scry 1, then draw a card. (Then exile this card. You may cast the creature later from exile.)

Young Blue Dragon

Young Blue Dragon // Sand Augury

The Ur-Dragon

Eminence — As long as The Ur-Dragon is in the command zone or on the battlefield, other Dragon spells you cast cost {1} less to cast.
Flying
Whenever one or more Dragons you control attack, draw that many cards, then you may put a permanent card from your hand onto the battlefield.

Ancient Gold Dragon

Flying
Whenever Ancient Gold Dragon deals combat damage to a player, roll a d20. You create a number of 1/1 blue Faerie Dragon creature tokens with flying equal to the result.

Thornspire Verge

{T}: Add {R}.
{T}: Add {G}. Activate only if you control a Mountain or a Forest.

Counterspell

Patchwork Banner

As Patchwork Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Spire Garden

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

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Plains

Korvold and the Noble Thief

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
III — Exile the top three cards of target opponent's library. You may play those cards this turn.

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.

Scaled Nurturer

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

Dragonborn Looter

{1}, {T}: Draw a card, then discard a card.

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.

Mountain

Cliffgate

Cliffgate enters tapped.
As Cliffgate enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Flick a Coin

Flick a Coin deals 1 damage to any target. You create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Draw a card.

Training Center

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

Vault of Champions

Vault of Champions enters tapped unless you have two or more opponents.
{T}: Add {W} or {B}.

Restless Vinestalk

Restless Vinestalk enters tapped.
{T}: Add {G} or {U}.
{3}{G}{U}: Until end of turn, Restless Vinestalk becomes a 5/5 green and blue Plant creature with trample. It's still a land.
Whenever Restless Vinestalk attacks, up to one other target creature has base power and toughness 3/3 until end of turn.

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

Hushwood Verge

{T}: Add {G}.
{T}: Add {W}. Activate only if you control a Forest or a Plains.

Alchemist's Talent

(Gain the next level as a sorcery to add its ability.)
When Alchemist's Talent enters, create two tapped Treasure tokens.
{1}{R}: Level 2
Treasures you control have "{T}, Sacrifice this artifact: Add two mana of any one color."
{4}{R}: Level 3
Whenever you cast a spell, if mana from a Treasure was spent to cast it, this Class deals damage equal to that spell's mana value to each opponent.

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.

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.

Firkraag, Cunning Instigator

Flying, haste
Whenever one or more Dragons you control attack an opponent, goad target creature that player controls.
Whenever a creature deals combat damage to one of your opponents, if that creature had to attack this combat, you put a +1/+1 counter on Firkraag, Cunning Instigator and you draw a card.

Niv-Mizzet, the Firemind

Flying
Whenever you draw a card, Niv-Mizzet, the Firemind deals 1 damage to any target.
{T}: Draw a card.

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet, Parun deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Dragonlord's Servant

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

Swamp

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Draconic Lore

This spell costs {2} less to cast if you control a Dragon.
Draw three cards.

Realm-Scorcher Hellkite

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
Flying, haste
When Realm-Scorcher Hellkite enters, if it was bargained, add four mana in any combination of colors.
{1}{R}: Realm-Scorcher Hellkite deals 1 damage to any target.

Nicol Bolas, Dragon-God

Nicol Bolas, Dragon-God has all loyalty abilities of all other planeswalkers on the battlefield.
+1: You draw a card. Each opponent exiles a card from their hand or a permanent they control.
−3: Destroy target creature or planeswalker.
−8: Each opponent who doesn't control a legendary creature or planeswalker loses the game.

Ruby Medallion

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

Korvold, Gleeful Glutton

This spell costs {1} less to cast for each card type among permanents you've sacrificed this turn.
Flying, trample, haste
Whenever Korvold deals combat damage to a player, put X +1/+1 counters on Korvold and draw X cards, where X is the number of permanent types among cards in your graveyard.

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

Sarkhan the Masterless

Whenever a creature attacks you or a planeswalker you control, each Dragon you control deals 1 damage to that creature.
+1: Until end of turn, each planeswalker you control becomes a 4/4 red Dragon creature and gains flying.
−3: Create a 4/4 red Dragon creature token with flying.