Here are some cell storage ideas:
This is originally a 12-to 20-gauge shotgun shell holder. There is just enough tension on the cells to keep them in-place. I added a piece of recycled foam to the lid to prevent any movement.
The liner can be removed, and the case used for P60 module storage - also a nice tension fit.
For AAs and AAAs, some handgun bullet storage cases work well:
I'm giving away some of these here: https://budgetlightforum.com/t/-/4061