startosinstall tool in the High Sierra installer supports adding additional packages that will be installed after macOS is installed, via the
bash-3.2$ /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/startosinstall --usage Usage: startosinstall Arguments --applicationpath, a path to copy of the OS installer application to start the install with. --license, prints the user license agreement only. --agreetolicense, agree to license the license you printed with --license. --rebootdelay, how long to delay the reboot at the end of preparing. This delay is in seconds and has a maximum of 300 (5 minutes). --pidtosignal, Specify a PID to which to send SIGUSR1 upon completion of the prepare phase. To bypass "rebootdelay" send SIGUSR1 back to startosinstall. --converttoapfs, specify either YES or NO on if you wish to convert to APFS. --installpackage, the path of a package to install after the OS installation is complete; this option can be specified multiple times. --usage, prints this message. Example: startosinstall --converttoapfs YES
A High Sierra NetInstall image built with System Image Utility has a similar option: you can add additional packages to the install:
Unfortunately, under both 10.13 and 10.13.1, both methods have a similar issue: if you try to install multiple packages, in some/many cases the installer will not properly cache all the intended packages and the install of macOS will fail with the message “The path /System/Installation/Packages/OSInstall.mpkg appears to be missing or damaged.” It tells you to restart and try again (which won’t work…).