Breadsticks are a great alternative to rice cakes.
Dried fruit (although not too much as v sugary)
Organix snacks - carrot sticks, cheese puffs, sweetcorn rings etc
Baby biscuits - Plum, Hipp Elephants, Organix etc. (or just plain rich tea biscuits)
Fruit - strawberries, blueberries, apricots and pears go down well in this house
'Poo bars' - Organix banana and date bars
Home made stuff - sugar free banana bread, all sorts of muffins etc
Malt loaf
Oatcakes
Or anything I can find in the cupboards really...