productboard - Beautiful and powerful product management.
KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
ProdPad - ProdPad helps your team gather ideas, surface the best ones and turn them into product specs, and then put it all on a product roadmap.
Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
ProductPlan - Cloud-based product roadmap software solution
QUCS - Qucs, briefly for Quite Universal Circuit Simulator, is an integrated circuit simulator which means you are able to setup a circuit with a graphical user interface (GUI) and simulate the large-signal, small-signal and noise behaviour of the circuit.