Based on a 2016 review of pet trade sales lists and other online information, the reptiles listed below (not in order of popularity) were consistently among the top mentioned and/or sold.
Bearded Dragon
Uromastyx (Spiny-Tailed lizard)
Green Iguana
Chinese Water Dragon
Green Basilisk
Brown Basilisk
Leopard Gecko
Crested Gecko
Long-tailed Grass Lizard
Green Anole
Brown Anole
Veiled Chameleon
Panther Chameleon
Savannah Monitor
Ball Python
Boa Constrictor
Corn Snake
Milksnake
Kingsnake
Rat Snake
Red-Eared Slider
Red-Footed Tortoise
Additional information about the natural history, distribution, classification, and conservation biology of each species can be found at The Reptile Database and Animal Diversity Web.