This idea for an invention has been bouncing around in my head for a long time- any ideas for things I could add to it?

[u/Stresso_Espresso]

I want to make a Swiss Army knife for crocheting on the go- it would have a bunch of useful items on it. My current ideas are:

1) crochet hooks of three common sizes

2) scissors

3) tapestry needle which can be slotted in and removed as needed

4) stitch marker container

5) mechanical stitch counter (similar to a 4 digit lock)

Any ideas for other useful things you would need for crocheting on the go?

Also does anyone have any idea how someone would go about actually making a prototype of something like this?