Visual Micro - Arduino IDE for Visual Studio and Atmel Studio
Visuino - Visuino is a visual programming environment that lets you write programs from Arduino circuit boards.
ArduBlock - ArduBlock is a graphical programming language plugin specifically made for Arduino circuits and controllers.
Embrio - Embrio is an all-in-one open-source visual and real-time development environment built on HTML and JavaScript.
XOD - A visual programming language for microcontrollers. Like code, but better.
PlatformIO - Next-generation IDE for IoT