That's what I thought also but they were all in different spots and they were deep down. I don't do your typical weeding I go all the way to the root. Lol
Nice finds. I have found a few agates and fossils while weeding the garden myself. I think Rustynailsandscrews is right, those don't just kind of look tumbled I would almost guarantee they were. How they ended up in your dirt is an interesting mystery.