Known apps with adaptive shortcut icons:
Element, Orgzly, Calendar, SELinuxModeChanger, SoundCloud

All of these shortcuts are created the same way, via long press from the main icon and dragging it to the desktop.
Anonymous
one more screenshot
I've added this to my todo - thanks for the tip, I hadn't realised one could drag the long-press shortcuts to be their own separate icons on the homescreen.