VeroRoute - Cross-platform software for producing Veroboard (stripboard), Perfboard, and single-sided PCB...

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

Virtual Breadboard - It is a circuit simulator on a virtual breadboard.

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

KiCad - A Cross Platform and Open Source Electronics Design Automation Suite

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.