CircuitLogix - CircuitLogix electronics lab simulation provides fast, powerful schematic design and simulation in one complete program.
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.
EasyEDA - EasyEDA - Web-based EDA suite; runs in 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
KiCad - A Cross Platform and Open Source Electronics Design Automation Suite
Ngspice - Ngspice is a mixed-level/mixed-signal circuit simulator.