f README.md: Related Projects

README.md

@@ -52,9 +52,14 @@ RIOT is licensed with LGPLv2.1, a copyleft license which fosters
 indirect business models around the free open-source software platform
 provided by RIOT, e.g. it is possible to link closed-source code with the
 LGPL code.
-
-[Ariel OS](https://github.com/ariel-os/ariel-os) is an offspring of RIOT written
+### Related Projects
+- [**Ariel OS**](https://github.com/ariel-os/ariel-os) is an offspring of RIOT written
 in Rust following RIOT's targets and [vision](https://doc.riot-os.org/vision.html).
+- [Contiki(-NG)](https://github.com/contiki-ng/contiki-ng) was an inspiration for starting RIOT, a operating system for constrained devices with a focus on networking.
+- [NuttX](https://github.com/apache/nuttx) is another general purpose microcontroller OS with a focus on bringing POSIX to MCUs
+- [RT-Thread](https://github.com/RT-Thread/rt-thread) is a microcontroller operating system with strong roots in China and a large community there, it has extensive support for MCUs from Chinese vendors, but also for western ones.
+- [Zephyr](https://github.com/zephyrproject-rtos/zephyr) is general-purpose operating system for microcontrollers, shepparded by the Linux foundation. 
+
 
 ## Features