So I got flushed with inspiration one day, then I decided to do a bunch of dragon heads, and here they are...

1. Draconis benthae giga-
lifespan: ?
size and weight: undefined
type: deep-sea

This dragon is also called the Leviathan. A relative species of Mala 'Brigo, this dragon is also a deep ocean kind. It is two things: the biggest, the oldest. Being one of the very first large creatures since life began, this dragon remains dormant and rests upon the Marianas Trench, off the coast of Philippines. Its anatomical structure is simple, like a glorified serpent-whale. The last time it was awakened, it caused a massive seismic anomalies and triggered successive tsunamis in Southeast Asia. For those who have seen it, its size cannot be determined because it cannot be seen in its entirety that fades beyond the horizon.

2. Draconis extraterrestriae-
lifespan: 90 earth years
size and weight: Length(13 ft.) Height(6 ft.) Weight( 850kg)
type: mutation

This species mutated 25 million years ago, when the great meteor hit the earth. Medium-sized dragons that migrated along the crater were exposed to radiation, and mutated a hyperactive skin that hardened with ever-growing calcium. Their entire biological signature was altered, and a new species of dragon was born. They are now part invertebrate, because their bones grew in place of their skin.

3. Draconis igneous-
lifespan: 200 years
size and weight: Length(500m) Height(100m) Weight(400t)
Type: land dragon

These dragons are one of the largest and heaviest land species. As the name implies, these dragons live nearby volcanic areas, because they feed largely on pyroclastic material present in the rocks. Adapting to the environment, their hide is literally as hard as rock, but still flexible. These dragons still have wings, but they use them primarily to bask in the scorching embers of volcanoes. Their exterior is just like the terrain they live in: rugged and rocky. When these dragons die, the heavy mineral content of their flesh is released, petrifying their corpses, which is why wealthy nobles take great pride in purchasing such grand monuments.

4. Draconis pyro pygmy
Lifespan: 30 years
Size and weight: Length(3ft) Height(6in) Weight(10kg)
Type: small firebreather

This species is one of the smallest of the dragons. Though quite miniature, these little creatures are most excellent at firebreathing, able to breathe fire up to 35 meters, that is why they are domesticated sometimes as guard dogs.

5. Draconis cavernensis
Lifespan: 120 years
Size and weight: Length(60m) Height(10m) Weight(30t)
Type: nocturnal

These dragons put the "ugh" in ugly. They are also called "Cave Wyrms", because they are found to inhabit spacious caverns, where unwary travelers meet a most grotesque end. Purely nocturnal, they never go out of their dens when there is still even a speck of light around... so it is advisable to bring a torch the next time you venture into a dark and spooky cave.

6. Draconis barracuda
Lifespan: 85 years
Size and weight: Length(20ft) Height(6ft) Weight(200kg)
Type: freshwater amphibian

This freshwater breed is also referred to as the "Spear Lizard", because of its sharp bony protrusion at the tip of its lower jaw, which it uses to catch large prey. They were first domesticated by orcs as a fishing aid, but in the late times of war,they are employed as a freshwater patrol escorts.

7. Draconis garuda
Lifespan: 150 years
Size and weight: Length(25m) Wingspan(100m) Height(10m) Weight(12t)
Type: flier

These dragons are considered to be the missing link between true dragons, and the gryphons which evolved much later. Humans were very keen to put these creatures to service, to bolster their aerial military prowess, because they know that these type of dragons are lighter and faster. They are covered with coarse feathers that evolved from scales, and the first beaks of any known dragon or gryphon anatomy.

8. Draconis Luna
Lifespan: 500 years, but they have the capacity to become immortal
Size and weight: Length(75m) Height(20m) Weight(50t)
Type: nocturnal, mutation

These are one of the rarest ones... seen in deep elven forests, and only... Only when the moon shines. Centuries ago, forest dragons encountered night elves, who were glad to treat them as sentient beings. As the years passed, these dragons changed, according to the lifestyle and arcane mystics of the night elves. Thus, they developed a sense of harmony and need with the moon. Their horns grow in such a way that they curve into a crescent, in semblance, which also glow in the moonlight, as seen in a spectacular display in the mating season when the blue moon rises.

9. Draconis extraterrestriae megas
Lifespan: 1000 years
Size and Weight: Length(1000m) Weight(300t)
type: deep-sea mutation

A variant of the meteor-mutated dragons, this one mutated from a very large deep-water dragon species. Not much is known about these creatures because of their rarity and irregular migration patterns.

10. Draconis Inferno
Stats: unknown
Type: doombringer

This dragon is the largest of all land dragons capable of flight. They say that it rests beneath the highest peaks of the earth, waiting for the fateful day when all would be destroyed, to create a new world.