Zardnaar
Legend
There's a lot you can do with the core 5e rules themselves. NPC statblocks explicitly can have racial traits added, for instance.
A few months ago, my players discovered a fortress that was run by "The General" and his army of... kobolds. They talked their way in to the General's rooms deep within the keep to find that he was, in fact, an ancient and slightly insane bronze dragon who had signed up to lead a military unit some centuries ago only to have all his soldiers killed. The kobolds moved in later and (taking advantage of the General's survivor guilt) posed as the soldiers. Over time, they came to see themselves as soldiers - rather helped by the rather more disciplined life meaning several of them actually survived long enough to be great wyrms themselves, with a bit of added INT and WIS along the way.
I modelled most of the kobolds as Veterans:
https://capsomere.earth.gkhs.net//command/npc/Veteran/Kobold
With the leaders being a bit tougher:
https://capsomere.earth.gkhs.net//command/npc/Gladiator/Kobold
And one or two wetwork specialists who hearken back to the species' roots:
https://capsomere.earth.gkhs.net//command/npc/Assassin/Kobold
(I posted ages ago about a statblock generator for NPCs. Now that all the NPC statblocks are OGL, it's nice to be able to use those links)
I do not want to go to overboard on making NPCs kobolds but I have thought of things like kobold scouts, veterans, knights, gladiators, archmage and priests.