Those of us on a low carb, healthy fat (LCHF) find that we rarely need snacks because the fats (and protein) fill us up and trains our bodies to consume our own stored fat as needed. You could look into approaching you problem this way, but, as you are using insulin, you would need to be very careful not to overdo you your doses and end up going hypo. Take advice!!
However, returning to your question, could I suggest cheese, hard boiled eggs, pork scratchings, an avocado, nuts, seeds.
Sally