There are some low carb breads in the supermarkets, they are often the seeded ones but the best way is to check the carbohydrates on the packet or website, you will find it is both carbs per 100g and per slice. They may be the same per 100g but as the slice is smaller you would be having less carb. Of course you could just have your usual bread but have half as much.
Real butter all the way, far less processed and tastes far better.
Crisps are surprisingly high carb but the 'puffy' ones are often lower carb but alternatives are nuts, pork scratchings or Protein bars like Nature Valley, KIND, Graze but again check the carbs per bar (bars are different sizes)
If you have filling meals with protein and healthy fats which would be better than having snacks.
This is a good link for some ideas for meals and also the introduction is a straightforward explanation of a way of managing the condition and reduce HbA1C and weight if you need to.
https://lowcarbfreshwell.com/