Your report describe several issues, it's normal that samba or ubuntu- retricted-extras are not listed. Krita being missing is a bug in calligra and doesn't only impact gnome-software, see bug #1576827 , muon is likely in a similar situation
** Changed in: gnome-software (Ubuntu) Status: New => Opinion -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-software in Ubuntu. https://bugs.launchpad.net/bugs/1579415 Title: Ubuntu Software Center does not display third party apps or all installed apps To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-software/+bug/1579415/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs