Mine are replaced in wrappers after use and stored flat on a bookcase.

I store mine standing upright on top of a shelf with book ends holding them up. I have been thinking of getting mail holders, but have not yet. There are some good ideas here. Thank you for posting this question!

i store mine in a tall kitchen trash can. i use a felt tip marker to write size of die on the ends so i can see at a glance which one i want.

Yes, the dies should not be stacked on top of each other. This could damage the blades. I put together 2 wire racks with cable ties and put my smaller dies in it. I found baskets at Home Goods for my strip dies. I need to go vertical versus horizontal with my storage.

The dies in the baskets are standing up leaning against the wall. I don't know why the other pic is turned.

Thanks for some great ideas! Mine are stored flat in their original packaging. I have about 20. The longest ones will give me more problems.

I store mine upright in a drawer in a long metal file cabinet. I currently store them in the thin plastic jackets they came in, however, these are falling a part so I have purchased some lightweight clear vinyl to make replacement jackets.