I don't have an overview I could provide you, but there's the HIDRemoteExample.app included in the HIDRemote SDK that shows you exactly this information when run.

Be warned, though, that the Plex Player profile contains programming errors (like f.ex. single button presses on the Harmony simulating several single button presses, so that one button press on the remote leads to the assigned action getting executed several times) and should therefore not be used with anything other than Plex, really.

For this, however, you can also just use the Virtual Remote to forward button presses to Plex.

If you're looking for a Harmony device profile with verified and intact Apple Remote button codes for use with Remote Buddy, please search for vendor "Iospirit" and device "Remote Buddy" in the Harmony software.

Cheers, 
Felix