kde widgets has some nice widgets e.g. an analog clock, i've been searching around on where the widgets / plasmoids are installed
it turns out it is in /usr/share/plasma/plasmoids/
and the clock i liked is org.kde.plasma.analogclock

and it turns out running that in a window is simple

> plasmawindowed org.kde.plasma.analogclock
or whatever widget name you can find in /usr/share/plasma/plasmoids/