Toy Boxes come in many shapes and sizes. However, toys come in even more shapes and sizes, and if your toy box is a simple open box you will soon realise that all the smaller toys become lost below the big ones. Either have a box for each size of toy, or buy one with separate compartments for storage.
Toy Boxes will, by their purpose, suffer more abuse than most other furniture, so check it for build quality and check the finish for knock-resistance [by gently pressing your fingernail into the surface].
If it has a lid, check the hardware is fit for purpose. If the lid is hinged, is there a risk of the lid nipping fingers? And there should be a lid support which has a nip-free action and fully supports the weight of the lid so that the lid requires some effort to push it down closed.
Children may use the toybox to climb into, so check that a child cannot become locked in or trapped.