I would put Local biscuit tin from São Tomé and Príncipe on the list for São Tomé and Príncipe because it is the kind of thing that feels useful once you are home, not just another airport purchase. Biscuits and dry breads are good because they survive the journey and are easy to share at work or with family. The reason it works is that it gives you a quick reminder of the trip without needing to keep a fragile ornament safe forever.