A cat toy is currently a useless item, and often considered as junk.
A cat toy has no use, being added purely for the purpose of clutter, creating more realism for the player when looting.
Cat toys can be found in wardrobes and in gift stores. They can also be found in glove boxes and on seats in vehicles.
From newitems.txt (Project Zomboid directory/media/scripts/)
Weight = 0.1,
Type = Normal,
DisplayName = Cat Toy,
Icon = CatToy,