FidoCADJ - FidoCadJ is a free user-friendly vector graphic editor for Mac OS X, Linux, Windows and Android.
LibrePCB - LibrePCB is a free EDA software to develop printed circuit boards.
XCircuit - XCircuit: Home Page
JSchem - Free Cross-Platform Schematic Editor
KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
Splan - sPlan is a software to design your schematic circuit diagrams.