MINIBLOQ - miniBloq is an open source graphical programming environment for Multiplo™, Arduino™, physical computing devices and robots.
ArduBlock - ArduBlock is a graphical programming language plugin specifically made for Arduino circuits and controllers.
PlatformIO - Next-generation IDE for IoT
Embrio - Embrio is an all-in-one open-source visual and real-time development environment built on HTML and JavaScript.
Arduino IDE - Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware...
XOD - A visual programming language for microcontrollers. Like code, but better.