RTOS list for Arduino

I have been evaluating RTOSes that will run on both AVR and ARM Arduinos. Any suggestions?

I am not looking for a best RTOS since each has features that are useful for various applications.

I have ChibiOS/RT ChibiOS free embedded RTOS - ChibiOS Homepage and FreeRTOS http://www.freertos.org/ running as Arduino libraries.

I am also looking at these since they have been use on the Arduino:

BeRTOS GitHub - develersrl/bertos: Bertos free RTOS: http://dev.bertos.org

QP Arduino Playground - QP-nano framework

scmRTOS https://github.com/MikeSmith/scmRTOS_Arduino

OSA OSA : Download [PIC24] for AVR8bit as well.

~~Salvo http://www.pumpkininc.com/~~

Femtoos http://www.femtoos.org/

AvrX http://www.barello.net/avrx/

http://trampoline.rts-software.org/

http://erika.tuxfamily.org/

http://picoos.sourceforge.net/