Pearl Dragon

Flying
{1}{W}: Pearl Dragon gets +0/+1 until end of turn.

Two-Headed Dragon

Flying
Menace (This creature can't be blocked except by two or more creatures.)
Two-Headed Dragon can block an additional creature each combat.
{1}{R}: Two-Headed Dragon gets +2/+0 until end of turn.

Rathi Dragon

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Rathi Dragon enters, sacrifice it unless you sacrifice two Mountains.

Zodiac Dragon

When Zodiac Dragon is put into your graveyard from the battlefield, you may return it to your hand.

Arcades Sabboth

Flying
At the beginning of your upkeep, sacrifice Arcades Sabboth unless you pay {G}{W}{U}.
Each untapped creature you control gets +0/+2 as long as it's not attacking.
{W}: Arcades Sabboth gets +0/+1 until end of turn.

Fire Dragon

Flying
When Fire Dragon enters, it deals damage to target creature equal to the number of Mountains you control.

Nicol Bolas

Flying
At the beginning of your upkeep, sacrifice Nicol Bolas unless you pay {U}{B}{R}.
Whenever Nicol Bolas deals damage to an opponent, that player discards their hand.

Teeka's Dragon

Flying; trample; rampage 4 (Whenever this creature becomes blocked, it gets +4/+4 until end of turn for each creature blocking it beyond the first.)

Crimson Hellkite

Flying
{X}, {T}: Crimson Hellkite deals X damage to target creature. Spend only red mana on X.

Vaevictis Asmadi

Flying
At the beginning of your upkeep, sacrifice Vaevictis Asmadi unless you pay {B}{R}{G}.
{B}: Vaevictis Asmadi gets +1/+0 until end of turn.
{R}: Vaevictis Asmadi gets +1/+0 until end of turn.
{G}: Vaevictis Asmadi gets +1/+0 until end of turn.

Lightning Dragon

Flying
Echo {2}{R}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
{R}: Lightning Dragon gets +1/+0 until end of turn.

Firestorm Hellkite

Flying, trample
Cumulative upkeep {U}{R} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Covetous Dragon

Flying
When you control no artifacts, sacrifice Covetous Dragon.

Exalted Dragon

Flying
Exalted Dragon can't attack unless you sacrifice a land. (This cost is paid as attackers are declared.)

Palladia-Mors

Flying, trample
At the beginning of your upkeep, sacrifice Palladia-Mors unless you pay {R}{G}{W}.

Chromium

Flying
Rampage 2 (Whenever this creature becomes blocked, it gets +2/+2 until end of turn for each creature blocking it beyond the first.)
At the beginning of your upkeep, sacrifice Chromium unless you pay {W}{U}{B}.

Volcanic Dragon

Ebon Dragon

Flying
When Ebon Dragon enters, you may have target opponent discard a card.

Alabaster Dragon

Flying
When Alabaster Dragon dies, shuffle it into its owner's library.

Cloud Dragon

Flying
Cloud Dragon can block only creatures with flying.

Catacomb Dragon

Flying
Whenever Catacomb Dragon becomes blocked by a nonartifact, non-Dragon creature, that creature gets -X/-0 until end of turn, where X is half the creature's power, rounded down.

Viashivan Dragon

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

Canopy Dragon

Trample
{1}{G}: Canopy Dragon gains flying and loses trample until end of turn.

Mist Dragon

{0}: Mist Dragon gains flying. (This effect lasts indefinitely.)
{0}: Mist Dragon loses flying. (This effect lasts indefinitely.)
{3}{U}{U}: Mist Dragon phases out. (While it's phased out, it's treated as though it doesn't exist. It phases in before you untap during your next untap step.)

Brimstone Dragon

Shivan Hellkite

Flying (This creature can't be blocked except by creatures with flying or reach.)
{1}{R}: Shivan Hellkite deals 1 damage to any target.