LTspice - LTspice® is a high performance SPICE simulation software, schematic capture and waveform viewer with enhancements and models for easing the simulation of analog circuits.
Logisim - Logisim is an educational tool for designing and simulating digital logic circuits.
Circuit Tree - Design and order Boards in Minutes
Hradla - Logical Network Editor that runs in your browser.
Pspice - OrCAD PSpice technology provides the best, high-performance circuit simulation to analyze and refine your circuits, components, and parameters before committing to layout and fabrication
Digital - A simulator for digital circuits.