Need suggestions! What to compliment this Tiffany necklace with

I suggest DBY as well for something a little extra but still subtle. Personally I don't layer my Tiffany necklaces because I only have 3 that aren't 16" (2- 18", 1- 30") and their styles don't really complement other things well imho. But I do love seeing other people layer! I think a silver DBY 16" would go lovely with that shopping bag pendant (if the necklace is still new you can go back into the store and upgrade to a 18" or 20", 18 is free and 20 is around $12 more).