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
Guitar Pro 7 - Create, play and share your tabs
ChordU - Extracts chords from any song, integrated YouTube.
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
Chordify - Chordify turns any music or song (YouTube, Deezer, SoundCloud, MP3) into chords.
OpenMPT - OpenMPT is a popular tracker software for Windows.
yalp.io - Automatic chords extraction from mp3 and YouTube