In addition to the ones mentioned.....I have two plums chopped with a dessert spoon of mixed seeds over them. The seeds add some fat and protein thus making the fruit more filling. Not too many mind as they are fatty, 15-20g is plenty.
I love the Carmans range of bars which are low GL. You will get them in health food shops or some supermarkets. In Ireland the supervalu supermarkets stock them.
The Nakd range of bars are great. They come in 30g and 68g bars. the bigger bar easily does me for a quick lunch with coffee if nothing gl friendly is available. The Nakd bars are in Tesco in the speciality food section.