Moomin mug is worth adding because it feels like something you actually noticed while travelling through Finland, rather than a generic souvenir. The trick is to choose the simple, well-made version. Small craft items look better on a shelf when they are not too shiny or mass-produced. The ideal version is modestly priced, not too bulky, and good enough that you would buy it again even without the holiday memory.
This is exactly the sort of thing I like bringing back from Russia: small enough to fit in a bag, but specific enough to remind you where you bought it. A simple toy works well if it reflects local craft or characters and is not too fragile. 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.
Nested wooden dolls painted in traditional or novelty designs.
Tiny handmade dolls traditionally placed under a pillow to carry worries away.