EasyEDA - EasyEDA - Web-based EDA suite; runs in browser.
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.
Antichamber - "A game with half of the attention to detail and imagination Antichamber has would be a smash hit - this bare-bones first-person puzzler is one of the most thought-provoking, engaging, and challenging video games ever developed.
TINACloud - Create Simulate and Design Circuits and their PCB layout with TINACloud
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
Ngspice - Ngspice is a mixed-level/mixed-signal circuit simulator.