Chordify - Chordify turns any music or song (YouTube, Deezer, SoundCloud, MP3) into chords.
Restore.Media - Got a corrupted video or audio file? No worries – Restore.Media can repair even the most severely damaged video and audio files where other tools fail. Try it free!
muted.io - A magical collection of interactive music theory tools & visual reference pages for musicians and music producers
untrunc - Restore a truncated mp4/mov. Improved version of ponchio/untrunc
soundrop - Soundrop is an app that allows you to create your own personalized sound track to keep you focused or relax.
Digital Video Repair - Digital Video Repair is freeware to repair (fix) MP4, MOV and AVI files having problems with playback or rewinding.