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.

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.)

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Exile any number of target players' graveyards. Draw a card.

Carnelian Orb of Dragonkind

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

Ancient Gold Dragon

Flying
Whenever this creature 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.

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.

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.

Bathe in Dragonfire

Bathe in Dragonfire deals 4 damage to target creature.

Dragonloft Idol

As long as you control a Dragon, this creature gets +1/+1 and has flying and trample.

Dromoka's Gift

Bolster 4. (Choose a creature with the least toughness among creatures you control and put four +1/+1 counters on it.)

Simic Signet

Ancient Silver Dragon

Flying
Whenever this creature 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.

Ojutai, Soul of Winter

Flying, vigilance
Whenever a Dragon you control attacks, tap target nonland permanent an opponent controls. That permanent doesn't untap during its controller's next untap step.

Door to Nothingness

This artifact enters tapped.
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice this artifact: Target player loses the game.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Titanic Growth

Target creature gets +4/+4 until end of turn.

Dragon Blood

{3}, {T}: Put a +1/+1 counter on target creature.

Blue Dragon

Flying
Lightning Breath — When this creature 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.

Ambitious Dragonborn

This creature enters with X +1/+1 counters on it, where X is the greatest power among creatures you control and creature cards in your graveyard.

Ancient Copper Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. You create a number of Treasure tokens equal to the result.

Chaos Dragon

Flying, haste
This creature attacks each combat if able.
At the beginning of combat on your turn, each player rolls a d20. If one or more opponents had the highest result, this creature can't attack those players or planeswalkers they control this combat.

Dragonlord's Servant

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

Plains

Island

Dragon's Claw

Whenever a player casts a red spell, you may gain 1 life.

Talons of Wildwood

Enchant creature
Enchanted creature gets +1/+1 and has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)
{2}{G}: Return this card from your graveyard to your hand.

Dragon Mage

Flying
Whenever this creature deals combat damage to a player, each player discards their hand, then draws seven cards.

Timeless Lotus

Timeless Lotus enters tapped.
{T}: Add {W}{U}{B}{R}{G}.

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.

Demanding Dragon

Flying
When this creature enters, it deals 5 damage to target opponent unless that player sacrifices a creature of their choice.

Dragon Shadow

Enchant creature
Enchanted creature gets +1/+0 and has fear. (It can't be blocked except by artifact creatures and/or black creatures.)
When a creature with mana value 6 or greater enters, you may return this card from your graveyard to the battlefield attached to that creature.

Dragonspeaker Shaman

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

Command Tower

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

Dragon Cultist

Commander creatures you own have "At the beginning of your end step, if a source you controlled dealt 5 or more damage this turn, create a 4/4 red Dragon creature token with flying."

Hellkite Overlord

Flying, trample, haste
{R}: This creature gets +1/+0 until end of turn.
{B}{G}: Regenerate this creature.

Dragon Arch

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

Forest

Dragon's Hoard

Whenever a Dragon you control enters, put a gold counter on this artifact.
{T}, Remove a gold counter from this artifact: Draw a card.
{T}: Add one mana of any color.

Atarka, World Render

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

Dragonborn Looter

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

Ancestor Dragon

Flying
Whenever one or more creatures you control attack, you gain 1 life for each attacking creature.

Mountain

Brainstealer Dragon

Flying
At the beginning of your end step, exile the top card of each opponent's library. You may play those cards for as long as they remain exiled. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.
Whenever a nonland permanent an opponent owns enters the battlefield under your control, they lose life equal to its mana value.

Thrakkus the Butcher

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

Sol Ring

Ancient Brass Dragon

Flying
Whenever this creature deals combat damage to a player, roll a d20. When you do, put any number of target creature cards with total mana value X or less from graveyards onto the battlefield under your control, where X is the result.

Dragon's Herald

{2}{R}, {T}, Sacrifice a black creature, a red creature, and a green creature: Search your library for a card named Hellkite Overlord, put it onto the battlefield, then shuffle.

Heroes' Bane

This creature enters with four +1/+1 counters on it.
{2}{G}{G}: Put X +1/+1 counters on this creature, where X is its power.

Clockwork Dragon

Flying
This creature enters with six +1/+1 counters on it.
Whenever this creature attacks or blocks, remove a +1/+1 counter from it at end of combat.
{3}: Put a +1/+1 counter on this creature.

Swamp

Adult Gold Dragon

Talons of Falkenrath

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature has "{1}{R}: This creature gets +2/+0 until end of turn."

Dragon Grip

Ferocious — If you control a creature with power 4 or greater, you may cast this spell as though it had flash. (You may cast it any time you could cast an instant.)
Enchant creature
Enchanted creature gets +2/+0 and has first strike.

Ancient Bronze Dragon

Flying
Whenever this creature 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.

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 this card from your graveyard to your hand.

Dragon Fangs

Enchant creature
Enchanted creature gets +1/+1 and has trample.
When a creature with mana value 6 or greater enters, you may return this card from your graveyard to the battlefield attached to that creature.

Artificer's Dragon

Flying
{R}: Artifact creatures you control get +1/+0 until end of turn.
Unearth {3}{R}{R} ({3}{R}{R}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Dragonlord Silumgar

Flying, deathtouch
When Dragonlord Silumgar enters, gain control of target creature or planeswalker for as long as you control Dragonlord Silumgar.

Gilded Lotus

Dragon Breath

Enchant creature
Enchanted creature has haste.
{R}: Enchanted creature gets +1/+0 until end of turn.
When a creature with mana value 6 or greater enters, you may return this card from your graveyard to the battlefield attached to that creature.