Kobolds of indiscriminate size!
I have long held the belief that kobolds do not actually ever stop growing. The problem, you see, is the short life expectancy of kobolds. They always die before they get too big. However, if a kobold did, somehow, ever survive for long enough, one would notice it getting larger and larger until it was as tall as a dwarf after perhaps two or three decades. If somehow this kobold lived further, maybe even into his fifties, he would be as large as a man. Longer still, no one knows how large one may become.
Legend does tell of a great kobold warrior who lived to be eighty and grew as tall as a troll. However, this is most likely apocryphal. No kobold could possibly live that long.