Black Dragon

Flying
Acid Breath — When Black Dragon enters, target creature an opponent controls gets -3/-3 until end of turn.

Dragonlord Kolaghan

Flying, haste
Other creatures you control have haste.
Whenever an opponent casts a creature or planeswalker spell with the same name as a card in their graveyard, that player loses 10 life.

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.

Green Dragon

Flying
Poison Breath — When Green Dragon enters, until end of turn, whenever a creature an opponent controls is dealt damage, destroy it.

White Dragon

Flying
Cold Breath — When White Dragon enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap 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.

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.

Sunscorch Regent

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

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.)

Akoum Hellkite

Flying
Landfall — Whenever a land you control enters, Akoum Hellkite deals 1 damage to any target. If that land is a Mountain, Akoum Hellkite deals 2 damage instead.

Dragon Hatchling

Flying
{R}: Dragon Hatchling gets +1/+0 until end of turn.

Mirrorwing Dragon

Flying
Whenever a player casts an instant or sorcery spell that targets only Mirrorwing Dragon, that player copies that spell for each other creature they control that the spell could target. Each copy targets a different one of those creatures.

Loch Dragon

Flying
Whenever Loch Dragon enters or attacks, you may discard a card. If you do, draw a card.

Vaevictis Asmadi, the Dire

Flying
Whenever Vaevictis Asmadi, the Dire attacks, for each player, choose target permanent that player controls. Those players sacrifice those permanents. Each player who sacrificed a permanent this way reveals the top card of their library, then puts it onto the battlefield if it's a permanent card.

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.

Hoarding Dragon

Flying
When this creature enters, you may search your library for an artifact card, exile it, then shuffle.
When this creature dies, you may put the exiled card into its owner's hand.

Adult Gold Dragon

Hellkite Punisher

Flying
{R}: Hellkite Punisher gets +1/+0 until end of turn.

Manaform Hellkite

Flying
Whenever you cast a noncreature spell, create an X/X red Dragon Illusion creature token with flying and haste, where X is the amount of mana spent to cast that spell. Exile that token at the beginning of the next end step.

Ruthless Deathfang

Flying
Whenever you sacrifice a creature, target opponent sacrifices a creature of their choice.