Dragonborn.
At a very base level, I love that they're a "proud warrior race" type that ISN'T simultaneously "brutish, stupid, and ugly." For real, 99% of "proud warrior race" types go in HARD for those. Orcs and hobgoblins being the most common examples, but there are many others--Dwarf is about the only partial exception, but they're also often portrayed as only knowledgeable in a narrow area (mostly smithwork and brewing), and tend to be drunken louts way, way, WAY too often, looking nothing like Gimli's warrior-prince archetype. Any race that has even a hint of refinement or poise is either a Dex-focused "lithe and agile beauty" or not actually inclined toward warrior pursuits at all, being all mages or priests. Dragonborn avert this completely. They are proud and noble of bearing, characterized as intense and focused, having a culture that may lean into arrogance but definitely avoids the "dumb brute" angle. Yet they are also very specifically physically strong and hardy, marrying mighty thews with winsome words and unyielding tenacity.
Beyond that, though, I love the story of fallen Arkhosia--a long-lost kingdom, one that was not perfect but was pretty damn glorious in its day. Something all dragonborn aspire to rebuild, even if for most that's a distant dream compared to just making it from one day to the next. I love the idea of a people separated by a vast geographic diaspora, yet united under a shared culture of oral and written tradition that has been passed, mother to son, father to daughter for centuries. "Never forget who we were. Never forget who we could be again." They're all at least a little history-literate, because attention to history, to the great legacies of those who came before, is so important to them and the scattered children of Arkhosia.
The stuff I add to them to make them better? First, I actively consider the differences that their physiology would entail. They mature incredibly quickly, their females don't need to stand around pregnant for 9 months, they need to consider that most people have access to a breath weapon, etc. These entail both purely artistic elements (e.g. "dragonborn literature probably has many metaphors for the fragility of youth, since their youth is so much shorter than a human's") and more practical ones too (e.g. "given they lay eggs, mature extremely quickly, and heal faster than humans, dragonborn likely have larger standing armies--fielding both men and women--and suffer fewer medical issues, meaning they can use smaller colonies and fight more effectively for the same population size").
Second, I work very hard to avoid making "proud warrior race" the end of their definition. It's a high-level gloss, not a fully accurate depiction. Dragonborn think big: legacies to last for a hundred generations, engineering projects that revitalize entire cities or reach up into the heavens themselves, artistic endeavors that bring the viewer or listener to tears. They don't accept halfway measures, and throw themselves fully into whatever they've chosen to do or be. This makes them both incredibly inflexible ("how dare you question the wisdom of your clan!/challenge the legacy of your forebears!") and capable of incredible change and transformation in a short time (founding a clan, becoming the legendary forebear others trace their descent from)--what lasts, lasts for ages; what changes, changes now, into what is right; and none of them hold back in their pursuit of whichever they have set out for. That doesn't mean they can't change their minds, but it requires perhaps a bit more effort than it would with others, not just because of their pride, but because of their dedication.
Finally...I make sure to add little flourishes and embellishments to individual characters to show that even within the above, there's tons of variation. I always have my dragonborn Paladins show a soft spot for children, for example, because they truly, deeply believe that children given the right lessons and merely the chance to become good people will consistently do so. I also tend to have them display a complicated relationship with the idea of titles of nobility. On the one hand, a queen worthy of the role should be obeyed thoroughly--almost (almost) without question, because such a king would not ask for absolute blind obedience; on the other hand, an awful lot of nobles are anything but, being crass, tyrannical, abusive, and demanding blind obedience, not true service to the cause.
