“Just moved to a new house, found this plastic tub of 3mm tiny balls hidden on top of a built-in cabinet.”
"Looks like dried-out Orbeez. Add water and let sit to see if they soak it up. May have had an odor at one time. My ex-wife used to use these with water and scented oils and they would soak it up and smell good for a few weeks and then you would just have to add more."
More likely an adhesive spreader for plastic tile, or to rough groove fresh concrete for traction.
#14 could be for keeping various plants on display. My grandmother had something similar for that, only with a few less shelves.