BookWidgets - BookWidgets is an excellent application that let you create engaging exercises in minutes and easily share a varied variety of beautiful and fun activities with your classroom and others.
ChordU - Extracts chords from any song, integrated YouTube.
Padlet - Visual boards for organizing anything.
Guitaa.com - Turn ANY song into chords, play along with interactive chords and diagram, transpose, loop, tempo control.
Socrative - Socrative helps teachers engage the class with educational activities to measure and visualize...
Chordify - Chordify turns any music or song (YouTube, Deezer, SoundCloud, MP3) into chords.