gPhoto (GNU Photo) is a set of libraries for previewing, retrieving,
and capturing images from a range of supported digital cameras to your
local hard drive. It does not support digital cameras based on the USB
storage protocol. Those can be mounted by Linux directly.

As of this time, gPhoto supports around 500 cameras, listed on:

http://gphoto.sourceforge.net/proj/libgphoto2/support.php

or by running

gphoto2 --list-cameras