There are near endless uses for ball bearings in toys. Their high mass-to-size ratio makes them ideal game balls for table hockey, Shoot-the-Moon style games, etc.
Where they really shine is for use with magnets or in marble towers. These are industrial quality, hardened-steel bearings with excellent chrome plating. At 9/16" diameter, they are not suitable for use in toys for children under age 3 because of the choking hazard, but are ideal otherwise.
Sold in packages of 10 or 50.
Made in USA.