PhotoRec 
PhotoRec is a data file recovery software that is designed for rcovering accidentally deleted files 
 (including documents, videos and images) from hard disks, memory cards and other digital storage 
 media. The software has been picture recovery successfully tested with different portable media players that include the  iPod and digital camera brands like Canon. Casio Exilim, Nikon, Pentax. Praktica, and more. 
 

Why you must get it: 
PhotoRec has been distributed under the GNU General Public License  or the GPLV v2+. PhotoRec was originally designed to be a more focused companion program to TestDisk. For the sake of safety, PhotoRec uses read-only access to handle the storage device the user is trying to data from. The software is also capable of recovering DD (raw) image files. This software will run on most versions of Windows and Windows Server, MacOS, Linux. Sun Solaris, OpenBSD. NetBSD and FreeBSD. This software supports recovery from a variety of filesystems like HFS exFAT, FAT, NTFS and ext2/ext3/ext4. One of the best features of PhotoRec  is that it will also work with storage devices going back a few generations from ROMs to hard disks, memory (yards Digital, SmartMedia, MMC etc.) and USB drives.