[MENTION=6775929]Puxido[/MENTION] - well if you visit the Cartographers' Guild, several of the posters of huge threads containing various map objects they've created. I post a few, but then I sell sets of map objects that I create, and half 2 sets currently available at DrivethruRPG, though as stated, these aren't free. I also have some one-off samples available on my G+ community.
Another site with both paid for and free map objects can be found at RPGMapShare.
You could also visit the many other Virtual Tabletop applications (other than Roll20) that have both free and links to paid for map object sets like: