As mentioned earlier, the Dīgambaras are most famous because many of their ascetics remain naked. They believe that Mahāvīra had transcended all bodily needs, so they emulate him by giving up any sort of protection for the body, such as clothes.
The name of this sect, Dīgambara, actually means “sky-clad,” meaning that they don’t wear anything but the sky (in other words, nothing). Ordinary followers of this sect can wear clothes, though.