Is there other GUI toolkits around that could run on bare metal on a microcontroller ? I have already seen GuiLite[0] being posted on HN, but I am not sure how

Is there other GUI toolkits around that could run on bare metal on a microcontroller ? I have already seen GuiLite[0] being posted on HN, but I am not sure how robust and easy to use it is. [0] https://github.com/idea4good/GuiLite https://github.com/idea4good/GuiLite