VCV Rack - A cross-platform modular synthesizer.
Bosca Ceoil - A free, easy to use tool for creating music.
Voltage Modular - Virtual modular platform designed for flexibility and pro sound
Renoise - Renoise is a digital audio workstation.
miRack - Eurorack-style modular synthesizer for iOS.
Zynewave Podium - Podium is a modern digital audio workstation (DAW) for Windows.