I would put Local soda or cordial from Belarus on the list for Belarus because it is the kind of thing that feels useful once you are home, not just another airport purchase. For drinks, I would bring a can or bottle for curiosity rather than fill a suitcase with it. I would look for it in a proper local supermarket, covered market, deli, pharmacy, gift shop or small producer rather than leaving it until the departure gate. Back in the UK, it is worth checking specialist shops first because they often stock a better version than a broad marketplace listing. The reason it works is that it gives you a quick reminder of the trip without needing to keep a fragile ornament safe forever.