LabVIEW - LabVIEW offers many of the functions you'd find in a traditional script-based programming language presented in a more intuitive visual interface ideal fo engineering.

Pure Data - Pd (aka Pure Data) is a real-time graphical programming environment for audio, video, and graphical...

myOpenLab - MyOpenLab is a platform for finished elements (program components) that can be linked together.

SynthEdit - Visual programming software to build your own synthesizer.

PyLab_Works - PyLab_Works is a free and open source replacement for LabView + MatLab, written in pure Python.

VCV Rack - A cross-platform modular synthesizer.