AMPLI.FI - Live online music community. Twitch for tunes.
Violin by Trala - Violin by Trala is a music learning app that is designed specifically for Violin users.
Bandlab - Capture, nurture, and collaborate on song ideas in the cloud
Metronaut - An app to help you play classical music
Soundstripe for Twitch - Free music for Twitch streamers
Piano2Notes - Piano2Notes is a web application and mobile that transcribes your piano tune into a digital word document.