One thing that can be said of the dragon sketch above, he certainly has personality! See more versions of Smaug here.
Here’s something different in the worldbuilding department, a selection of randomgen* dragons for writing or gaming use, generated from lists of different characteristics like color, size, and type of treasure horde.
A few random dragons
A large but graceful male dragon with moss-green scales and a pair of cruel, curved horns, Vinaunt likes to hoard bejeweled chalices and emits searing flames. In manner he is irritable yet garrulous, with a self-aggrandizing bent, titling himself “The Despoiler Prince.” About him hangs the abominable smell of brimstone and sulpher.
Ixanth is a long and lean Asian dragon with gold-keeled scales and cheek and chin horns. He hoards luxury goods, horseshoes, and rare herbs, and breathes out hurricane-like gusts of wind. His manner is tranquil and cautious. Ixanth has a great yen for asking riddles, and his long ears twitch with favor when someone answers them successfully.
A stocky male dragon with supple bronze scales, Magrex’s flanks are covered with iridescent gold bars in a pattern like a python’s. He collects all that is precious and valuable and emits ghostly green fire from his mouth. He has an unpredictable manner and is able to shapeshift into human form, in which he once ruled a kingdom in disguise.
A medium-sized male dragon with gray scales and silver horns, Sritrisk hoards only platinum. He often disguises himself as a human sage with a brusque way of speaking. His breath weapon is a lightning bolt that destroys anything in its path. He has a narrow snout and small, hooded eyes. Sritrisk appears to honor the law, as he is always careful to keep his word while in human form.
Pewoth is a small but deadly female drake with pale green, crenallated scales and branching horns like the antlers of a deer. She collects human mummies. She has a cruel manner and never speaks, preferring to roar, and attacks with green-tinged flames. Pewoth has an odor of flaming musk and is especially malicious, prone to razing entire villages.
This ancient female dragon is black banded with light gold stripes. She collects jade and silk clothing and breathes out a blinding, blistering gas. She is normally sleepy and quiet, but evinces an inquisitive temperament when strangers venture into her territory. U’aut uses telepathic speech that sounds like thunder. She has a falcon’s golden eyes.
Ixva is a small, slim female dragon with gray-green scales and a membranous frill on her neck. She collects jewelry, pelts, and furs, and sprays out acid as a breath weapon. She is very intelligent, but reclusive. Halfings call her “The Gaunt Fury.” She has a throat patch of bright gold scales she is very proud of.
Hiszba is a large, mature, female dragon with bright red, keeled scales and large finned ears. She breathes out a hallucinogenic cloud of gas as a weapon. She also lures men to their doom with her singing chin bristles. Hiszba lairs underground in a vast cave complex she shares with her many offspring. She loves to collect jewelry and expensive writing utensils.
* Randomly generated