LXDM might be the only other major DE related display manager not in the list as well. Although, LXQT (the future version of LXDE) seems to be using LightDM as their display manager at the moment. https://github.com/lxde/lxqt-lightdm-greeter Based on the Qt nature of the new version, they also seem to be leaning towards switching to SDDM.