Для openSUSE Slowroll запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/X11:COSMIC:Factory/openSUSE_Slowroll/X11:COSMIC:Factory.repo
zypper refresh
zypper install pop-icon-theme
Для openSUSE Factory запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/X11:COSMIC:Factory/openSUSE_Factory/X11:COSMIC:Factory.repo
zypper refresh
zypper install pop-icon-theme
Для 16.0 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/X11:COSMIC:Factory/16.0/X11:COSMIC:Factory.repo
zypper refresh
zypper install pop-icon-theme