Rescue data

Tools

Foremost

http://foremost.sourceforge.net/

Foremost retrieves files from a disk or image based on header and footer data, so it can retrieve deleted files, as long as there wasn't a new file written over the same place on the disk. Follow the instructions, except use "sudo make install" instead of just "make install" if making it on mac. Use it on an image of the bad disk, not the bad disk itself, and certainly don't ever try writing the rescued files onto the disk/image you're rescuing, since that might overwrite the files you're trying to rescue.

dd_rescue

GNU ddrescue