Crowdin - Localize your product in a seamless way
1BITDRAGON - 1BITDRAGON is a user-friendly music creation software that allows anyone to make music without having to be an expert or have thousands of dollars of gear.
POEditor - The translation and localization management platform that's easy to use *and* affordable!
OnlineSequencer.net - OnlineSequencer.net is an online music sequencer that allows users to create beats and music tracks.
Lokalise - Localization tool for software developers. Web-based collaborative multi-platform editor, API/CLI, numerous plugins, iOS and Android SDK.
GoatTracker - This is a crossplatform C64 music editor.