Tune Sweeper - Show duplicates in your Music library. Automatically select which duplicates to keep and delete based on your preferences. Remove duplicates with one-click from your iTunes or Music app library.
CCleaner - CCleaner cleans, speeds up and frees up space on business endpoints.
iTunes Duplicate Song Manager - iTunes Duplicate Song Manager with Folder Watch removes iTunes duplicates in Windows and Mac OS X.
Glary Utilities - The No. 1 Free, Powerful and All-in-one utility for cleaning your PC
Dupe Eliminator for iTunes - iOS, iPad, iPhone, iPod Touch, iTunes, iTunes software, Software for iTunes, mobile iOS apps for iPad, iPhone and iPod Touch. Remove iTunes duplicates. Stream iTunes Music Library. Super iTunes Suite of useful tools.
BleachBit - When your computer is getting full, BleachBit quickly frees disk space.