Well, since there is artwork posted of a Kobold Queen - https://www.furaffinity.net/view/58624954/ and a Kobold Chief - https://www.furaffinity.net/view/58830590/ . I had decided to post up what a common kobold looks like, which is this one here. Most kobolds height tends to be between 3'10"-to-5'10" tall, but the average ones tend to be about 4-foot-tall, and seem pretty generic in appearance wise, heck males, females, futas, any gender doesn't really show a difference.

But the difference happens is when a kobold is given a name, either given one by the Kobold Queen, Kobold King, Kobold Chief, or a Master that chose to have them in their service. Depending on the one, it'll result a strong deep bond between the kobold and their leader/master, and if their master is very strong, it could cause an evolutionary change for a Common Kobold, possibly and most likely become a stronger unique variant, or very rarely become a new king, queen, or chief.

Any wild kobolds would often seek for a new master it views as worthy to serve, or detect a scent of a queen and they would tend to gather and service their new Kobold Queen. And of course, the Kobolds are very voracious and could gulp down a large creature down whole, maybe could pack away about 20-humans before reaching their limit, which will immobilize them if they're too heavy bu they could use their own strength to lift the belly to move around. They do have a storage stomach in which the ones chosen to hunt food would capture and store prey inside their storage stomach and bring it back to the clan and present the food to the leader of the clan. When they're leader is satisfied, the kobolds would devour their gathered prey as food (if you got captured by the kobolds, better hope their leader is convince to spare you, or you will be food).

This design of the Common Kobolds was made by me:  Josephiroth