@happyborg @trashheap @alienghic @veronica
If you didn't check the box during install, run 'sudo tasksel' and you will be presented with the same options.
For finer grained control on what gets installed (WRT DEs) search for the Debian Wiki on your desktop of choice. There are meta-packages that pull in more or less of what you want.
(Debian desktop user here - KDE/Plasma FTW.)