Most of my stencils are stored in files; the little black ones are A5 display books, the grey one is a 3-ring binder, and the final one is a scrapbook album measuring 12" x 12".
The A5 display books are for my small stencils.
I wrote the names, sizes, and suppliers on small cards

Most of my medium-sized stencils are in a 3-ring binder.
Some stencils in the three-ring binder have holes punched, so they don't require sleeves, but the majority are in protective sleeves.

Some of my favourite stencils.