VSTPLANET : VST Plugins Free - Virtual instruments and effects
meSing.js : meSing.js is a JavaScript singing synthesis library that uses the Web Audio API's DSP capabilities in conjunction with the meSpeak.js speech synthesis...
Glicol : make music with code. connect different nodes like a synth, sequencer or sampler.
Opentape : Opentape is a free, open-source package that lets you make and host your own mixtapes on the web.
Upload songs (via web or FTP), reorder, rename, cust...
librosa : librosa is a python package for music and audio analysis. It provides the building blocks necessary to create music information retrieval systems.
ixi audio is an experimental project concerned with the creation of digital musical instruments and environments for generative music.