Snacks.... well I normally don't do snacks as I find I'm satisfied after eating - but if I ever do get the munchies I have always got something low carb on hand - stuff like very high % chocolate (I like a couple of squares of Lindt 90%), then for the crunch I go for pork scratchings - I did try beetroot crisps and some mixed root veg crisps which were okay as far as my BG went but unfortunately I didn't like the taste or texture. I suppose, in addition to the chocolate, the things I snack on most are a small square of cheese, some cold low carb sausages, cold chicken or I will have a few raspberries.
If you are in to cooking there are loads of recipes out there for low carb snacks or cakes - some of them are really lovely - but I find if I get in to the baking and eating of cakes I will put on weight so I save the cakes for special occasions.