TinyCAD is an open source schematic capture program for MS Windows.
Tinkercad is a super easy-to-use, browser based 3D design tool.
Solve Elec is a free educational program to draw and analyze electrical circuits.
It is a circuit simulator on a virtual breadboard.
MeowCAD is an online free and open source electronic design application tool.
PCB Elegance is a suite of circuit board design tools for Windows.
For engineers who want to expand the possibilities of power electronics.
Schematics.com empowers engineers to design, share, and collaborate on circuit design online.
EasyEDA - Web-based EDA suite; runs in browser.
Ngspice is a mixed-level/mixed-signal circuit simulator.
E-Sim is a simulation of modern world.
Animated electronic circuit simulator using ideal components to visualize voltage and current.