Many packages create groups or even users that are left around after the package is removed. This can even lead to warning messages during boot. For example, if colord is no longer installed you can remove the colord user/group with userdel/groupdel.
]]>polkitd:!::
ntp:!::
colord:!::
systemd-journal-gateway:!::
systemd-timesync:!::
systemd-network:!::
systemd-bus-proxy:!::
systemd-resolve:!::
input:!::
systemd-journal-remote:!!::
systemd-journal-upload:!!::
git:!::
proc:!::
nvidia-persistenced:!::
systemd-coredump:!!::
Can any of that be deleted?
]]>