Embedded JavaScript engine for C/C++
Apache NuttX is a mature, real-time embedded operating system (RTOS)
Eclipse ThreadX is an advanced real-time operating system (RTOS) designed specifically for deeply embedded applications.
Modular and configurable OS for embedded applications
LVGL is a free, full-featured embedded UI library for devices from small MCUs to 3D-capable MPUs, enhanced by LVGL Pro, a professional editor and tooling.