Got some official smart part numbers and descriptions here. I have no idea if they're still available for sale:
A4518140007 Net Set for Luggage Compartment, black (I believe I had this, but I don't remember what it comes with).
A4518100080 Luggage Compartment Management System, black
A4518990021 Cargo Area Tray, black (I actually had this one, comes with velcro attachments so it doesn't slide around in the trunk).
A4518600174 Protective Divider Plus, coupe, black (I also had this one. A little challenging of an install).
A4518600274 Protective Divider Plus, cabrio, black
A4518100009 Luggage Cover, black
A4518900254 Safety Plus Package (I had this, nice tidy package for the compartment inside the tailgate flap).