FidoCADJ - FidoCadJ is a free user-friendly vector graphic editor for Mac OS X, Linux, Windows and Android.
KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
XCircuit - XCircuit: Home Page
Proteus PCB design - Proteus PCB design combines the schematic capture and ARES PCB layout programs to provide a...
JumboCAD EDA - JumboCAD EDA contains 3 packages, Schematic Capture, PCB designer and Library Editor.
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.