Spain
Traditional hard almond nougat eaten especially around Christmas.
Spain
I would put Smoked paprika pimentón on the list for Spain because it is the kind of thing that feels useful once you are home, not just another airport purchase. The best version is usually the sealed jar, tin or packet from a normal supermarket, spice stall or food hall, not the most expensive tourist version. The reason it works is that it gives you a quick reminder of the trip without needing to keep a fragile ornament safe forever.
Spain
Cured Iberian ham with rich, nutty flavour; best sliced thinly.
Spain
Rioja wine is worth adding because it feels like something you actually noticed while travelling through Spain, rather than a generic souvenir. Wine is a great memory of a meal, but I would wrap it carefully and only carry it when the luggage situation makes sense. The ideal version is modestly priced, not too bulky, and good enough that you would buy it again even without the holiday memory.
Spain
This is exactly the sort of thing I like bringing back from Spain: small enough to fit in a bag, but specific enough to remind you where you bought it. Look for a boxed version with a decent date on it, especially if you are buying it near the start of the trip rather than at the airport. It is also the kind of thing you can talk about when someone asks what you brought back, because there is usually a little story attached to where you found it.
Spain
When I think of an easy, crowd-pleasing thing to bring back from Spain, sherry vinegar is a good pick because it does not need much explanation when you hand it over. Oils and vinegars work well when the bottle is small, sealed and wrapped in clothing inside checked luggage. I would rate it higher when it is locally made, clearly labelled and easy to use at home, and lower when it is just tourist packaging.