I snack on thin wholegrain rye with sesame seeds crispbreads from Lidl. They are low GI and work for me but you need to test to see how you react. Sometimes I have them with a sardine and tomato paste and at other times very thinly sliced cheddar cheese and some pickled onion.
If you find that it works for you, and a couple of crispbreads probably will be OK, maybe even 3 or 4, you can move onto the gourmet stuff.
Peters Yard rye crispbread or Dr Kargs. Both are to be found in speciality foodshops. Both are expensive but you don't need more than say 1 Dr Kargs. They are both very hard and tough, so you need good teeth.
Dr Kargs have stuff like Emmental and Pumpkin seed, you only need a little butter. It is wheat, not rye like Peters Yard but at least it is proper wholegrain.
It's worth experimenting to find what works and what does not work. I keep some or all of these in the kitchen as well as Ryvita and some
Finn Crisp Thins. I keep lots of pickled, onions, gerkhins, chillis etc and sometimes mix spices with low fat cream cheeses and use them as spreads. The idea is to make a real meal out of things which have lots of crunch and very strong and sharp tastes. You feel like you have eaten something then and unlike a packet of crisps or biscuits, you don't feel you still need more to satisfy your hunger.
An ice cold zero cal zero carb lemonade with freshly squeezed lemon juice in it will make you whince and halt hunger pangs in an instant. Make sure it is very cold, very fizzy and very very lemony. The lemon juice by the way is good for helping to reduce BG levels and, if you put in the yellow flesh of the lemon, it is a good soluble fibre. Again, if you can find them, there is the gourmet Amalfi Lemon. You can eat the flesh. One lemon goes a long way when you use the slices wisely.
The next best tip,
Mezetta Hot Banana Wax Peppers, very hot and very crunchy. Best followed by a slice of amalfi lemon.
You won't go back to rich tea biscuits. Digestive biscuits are probably better anyway because of the higher fibre content. But, you start on these things and the next you know, it's chocolate hob nobs and then the ones which have a thin layer of caramel too. Best not go down that route and retrain your palette, crunchy, sharp, spicy tastes.