3D printing has opened up a new world for creative minds. With the right designs, one can print any number of items. But we got tired of toys and gadgets and wanted to find truly useful things we could download and print today. From lamps to cooking utensils, paper shredders to drones, Bluetooth speakers to grocery bag holders, we’ve found 15 of the best downloads on the internet. Some assembly may be required, but it's all free.