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.
Chordify - Chordify turns any music or song (YouTube, Deezer, SoundCloud, MP3) into chords.
yalp.io - Automatic chords extraction from mp3 and YouTube
UltimateGuitar.com - Learn how to play your favourite songs on guitar or ukulele
UkeLib - Ukulele Chords - A comprehensive library of ukulele chords with suggested finger positions for every chord.
Riffstation - The web version is Free and you can learn how to play Chords with Youtube Songs.