The best addition is the one you will enjoy keeping. Start with what draws you to it.
Maybe it is the color you remember, the controller missing from your setup, or a piece you have been looking for. Let that guide your shortlist, then compare the details.
Have a particular colorway in mind? Contact GrailClub with its name and what you are looking for. Ask about the item itself, not just the reference color, so you know what you are choosing.