Mixed in Key - Mixed In Key is award-winning DJ software that gives you the #1 technique of the world's best...
KeyFinder - Key estimation software for DJs
Tunebat - A browser based song key and bpm database. Supplies compatible songs for harmonic mixing.
Similarity - Similarity - Remove similar, duplicate MP3, music, audio files by content, tags. Check your music collection quality, remove unquality music. Organize your music collection.
foo_bpm - A component for calculating the BPMs (beats per minute) of any tracks in Foobar2000.
tuneXplorer - Multithreaded BPM and Key detection software for MP3 files.