1lyrics - 1 lyrics is one app for all your lyrics need.
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.
Musixmatch - - World’s Largest Lyrics catalog and official
iTunes Duplicate Song Manager - iTunes Duplicate Song Manager with Folder Watch removes iTunes duplicates in Windows and Mac OS X.
MetroLyrics - MetroLyrics is a searchable lyrics database featuring 1,000,000+ song lyrics from 20,000 artists. Use MetroLyrics to find your favorite song lyrics.
SongGenie - SongGenie analyzes, identifies and repairs your mp3 tags and names.