From the website:

Disk Drill, Mac Data Recovery Software, recovers data from HFS/HFS+, FAT, NTFS & other file systems right from your Mac. It helps you undeleteMac OS files using its 2 powerful Mac recovery methods: quick or deep scanning. Disk Drill data recovery locates and recovers deleted files from any mountable media like your main drive, external hard disk, memory cards, etc. Disk Drill can recover photos, music, documents, applications and many other known formats.

via Disk Drill – Mac data recovery software. Recover lost data easily!.

I have never used this software but it is free and worth trying.  Data Rescue doesn’t always do the job which is one of its competitors.