Some things I havn't recorded any where else:
QCad: Open Source 2D CAD. QCAD is a crossplatform CAD solution for Windows, Mac OS X and Linux. It supports the DXF format and optionally the DWG format (through a proprietary plugin) - qcad - with a professional version at a very attractive price
Qucs - Quite Universal Circuit Simulator. - 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. After that simulation has finished you can view the simulation results on a presentation page or window.