This is my design of hobby knife (scalpel) holder.

This thing will hold up to:
6 hobby knifes with diameter of 8mm
1 hobby knife with diameter of 11mm
6 boxes with spare blades with footprint up to 12x16mm

This holder is little bit special, because it works as holder and blade cover at same time. Just store hobby knifes with blade down. I have made cutouts from knife holes to hold blades bigger than handle, so there is no need for blade caps at all.

It will help to have every hobby knife with some color to easily recognise what you are searchnig for if you are using different tools in handles.

You can buy something like this:
https://www.aliexpress.com/item/4000370842941.html?spm=a2g0s.12269583.0.0.5e05574cUw3eKH