If you're after snacks that don't raise your BGs, then here's a list of what I have: nuts (some have a lot of carbs in though, I go for peanuts or Morrison's mixed nuts, 50g), peperami, pork scratchings (too noisy for the office though!), cheese, celery, coleslaw, 85% dark chocolate.
For me 10g of carbs will raise my BGs by 2-3 mmol/l. So if I need something to raise my BGs I'll have >=10g carbs, otherwise I aim for <10g carbs. A good way to find this out is to get hold of some dextro tablets, which contain 3g dextrose (very similar sugar to glucose) per tablet. Have 3 of them, test before about 30 mins - 1 hour after (they're very fast acting) and see what the difference is in BGs.
Edit: Just realized I've attempted to answer your original question after about 10 other posts! Oops, sorry!