muted.io - A magical collection of interactive music theory tools & visual reference pages for musicians and music producers
Guitar Pro 7 - Create, play and share your tabs
Chordify - Chordify turns any music or song (YouTube, Deezer, SoundCloud, MP3) into chords.
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
Scale Heaven - Browse and play any scale/chord, chord progression.
OpenMPT - OpenMPT is a popular tracker software for Windows.