Arduino IDE - Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware...
PhET Interactive Simulations - Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations.
B4R - Development tool for native Arduino programs.
Amanogawa.com - A wide range of applets on transmission lines, electromagnetic waves and antennas
PlatformIO - Next-generation IDE for IoT
ACD/ChemSketch - ACD/ChemSketch for personal and academic use brings the power of our structure drawing package to your home computer.