A cat's definition of a cool toy is one that offers novelty, interesting sounds and opportunities for interaction. Some of the best options include balls with rattles or bells inside them, catnip mice or balls, and an assortment of everyday objects.
Most cats love corrugated cardboard boxes and paper bags as aids to games of hide-and-seek. They also like clawing at these objects. They will happily bat and chase balls of crinkled paper, aluminum foil or plastic, but balls must be too large to swallow, and the cat must not be able to chew the object into pieces that it can choke on. Cats love wands with dangling toys that they can bat or pounce on. Toys with tinsel, string or small pieces that a cat can easily separate from the toy and swallow should be avoided.