Most of the western US high plains deserts are quite similar. Sagebrush, junipers, pinion pines, cedar and cotton woods with red dirt soil or silty sand mixed with alkaline. Image search on Moab, death valley, black rock desert for interesting terrain features. The saguaro (tree-sized cactus) and Joshua tree are probably the most interesting plants for tilesets. Sun-bleached skulls and bones sound cool but look bad if overused as objects models C5-c10 or replace standard tileset bush and water object models.
Imladris tileset is an excellent example of Glest fantasy object models.
An Aussie outback tileset with eucalyptus, thornbrush and assorted billabong and other surface texture types might also be interesting.
