The well known shop Tomtar and Troll in the old town (stockholm) is worth a visit.
Here you can buy both Tomtar and Trolls based on creatures from ancient Scandinavian fairy tales. (more down to the left "information/the story")
They are entirely handmade by the Swedish artists Kicki and Maija and are available in all imaginable sizes.
If you are looking for a unique souvenir you will surely find it here!