TuneFind - Tunefind contains an index of music and songs appearing in popular television shows and movies. Find a song, or see where an artists music has been featured.

Mixed in Key - Mixed In Key is award-winning DJ software that gives you the #1 technique of the world's best...

Shazam - Shazam is a mobile app that recognizes music and TV around you.

KeyFinder - Key estimation software for DJs

AudD - Basically, Shazam API. Recognize music in microphone recordings, audio files, and UGC. Identify songs playing on radio stations and audio streams. Or make your own music recognition app. Recognize music from social networks and analyze trends.

Tunebat - A browser based song key and bpm database. Supplies compatible songs for harmonic mixing.