I adore the fifth one. kobolds are an odd thing to work with since they are, in folklore, invisible. and for the most part seeing one usually meant you were going to die, from a mine collapse or your ship sinking. Or it would show itself to you just to make you cranky and tell you it was going to stick around and anoy you forever.
I've personal grown partial to the Kobalds of
Goblinscomic.com and have always imagined them to e fairly similar to various reptiles like the three toed skink for their affinities to water, caves, and really any place warm they can scoot into. Never saw them as anything similar to dragons except for the reptilian aspect, sometimes Ive even sketched them with fur, but their body type has always been reptilian to my eyes.
The image from kobald quest always annoyed me cause it simply looks like a mud brown goblin with long arms. granted there is only so much you can do if you want a sapient face. which is why I like the more reptilian face since they usually come into the thought process after you've locked down 6 or so Sapient faced races. (human, elf, dwarf, goblin, gnome, orc, etc.) I mean your dorfs get anoyed at having the same booz all the time, why do all the sentient races have to have sapient faces on top of apient bodies?