PICSimLab is a realtime emulator for PIC, Arduino, STM32, ESP32, ...
IDE for modeling and simulating discrete systems
AVR simulator IDE
A multi-modeling and simulation environment to study complex systems
The Vienna Topography Simulator
VEX Robotics Competition Simulator
Visu@lGrid - IDE for Building BOINC Projects
realistic truck & car simulator, with OpenGL graphics
N-body gravitational simulator