One of my favorite species that I feel is very underrated would have to be Pachydactylus rangei (web footed gecko). I have not had this species for long but it was always a long term goal of mine to acquire a pair.
I got my pair from John Zabroski of Elusive Exotics at NARBC-Tinley Park this October. P. rangei is one of the most interesting and entertaining species I have kept so far. They are veracious hunters and for their small size, only a few inches, they are surprisingly tame. One of the remarkable things about this species is their transparent skin. Looking at them, you can see their bones and veins, and also watch eggs develop inside of a gravid female. My other favorite features about this species are their webbed feet and ability to walk on the surface of the sand. They also love to dig moving more sand around their enclosure than any other terrestrial species I currently keep.
One interesting thing I recently learned is beacause of their transparent skin they can be sexed almost right out of the egg. You shine a light through them and you can actually see the organ that forms into a hemipene in males.
(animal photos by the author)