Guitaa is a free online music platform for musicians, that lets them find chords of any song of their choice on Guitar, Piano and Ukulele.
App:
Perfect app for musicians
ChordU - Extracts chords from any song, integrated YouTube.
Flowkey - The easiest way to learn piano with your iPhone or iPad
Chordify - Chordify turns any music or song (YouTube, Deezer, SoundCloud, MP3) into chords.
La Touche Musicale - With La Touche Musicale, you can learn piano online easily with the songs you love. Discover a fun and effective learning method to progress very quickly.
yalp.io - Automatic chords extraction from mp3 and YouTube
Virtual MIDI Piano Keyboard - Virtual MIDI Piano Keyboard is a MIDI events generator and receiver.