ChordIQ - Learn notes, chords, sight reading, perfect pitch and more.
Padlet - Visual boards for organizing anything.
ChordU - Extracts chords from any song, integrated YouTube.
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.
Chordify - Chordify turns any music or song (YouTube, Deezer, SoundCloud, MP3) into chords.
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.