Russia
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.
Russia
Nested wooden dolls painted in traditional or novelty designs.
Russia
I would put Russian caravan tea on the list for Russia because it is the kind of thing that feels useful once you are home, not just another airport purchase. It is a good one because people can try it slowly at home, and it makes a nicer gift than a mug with a place name printed on it. The reason it works is that it gives you a quick reminder of the trip without needing to keep a fragile ornament safe forever.
Pryaniki gingerbread is worth adding because it feels like something you actually noticed while travelling through Russia, rather than a generic souvenir. Biscuits and dry breads are good because they survive the journey and are easy to share at work or with family. The ideal version is modestly priced, not too bulky, and good enough that you would buy it again even without the holiday memory.
Russia
When I think of an easy, crowd-pleasing thing to bring back from Russia, buckwheat groats is a good pick because it does not need much explanation when you hand it over. Grains, pasta and rice are not glamorous, but they are useful, cheap and often taste different from the UK supermarket version. 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.