If I have a hexa left, and a couple of syns, i like to have an options hot choc made with skimmed milk. But if it needs to be totally free, i guess most kinds of fruit would be good, maybe with a mullerlight?
If you like grapes, you could try freezing a few. I really like them frozen - a bit like mini ice lollies! And i find i take longer to eat them, which must be a good thing.
Also, if you save some hexa, you could make up a load of syn-free rice pudding one day, and then have a bit of that in the eve when you're hungry, as its slightly more substantial than fruit.