Egg sac with ridges?
Depending upon its size, that may be the pupal case (the non-feeding life stage) of a Little House Fly, Fannia canicularis.
To determine if that is so, put several in a clear container with a porous lid of perhaps a paper towel held in place with a rubber band. Set it on the counter where you'll see it every day, but not n the sun. Then wait to see what, if anything, happens next, and send an image of what you see.