Dog Toys
Regardless of whether you have an active or lazy dog if they get bord they can quickly become distructive either chewing on things that they shouldn't or trying to find ways to escape your backyard.
Chew Toys
These often come in the shape of a bone or other similarily chewable form, one thing to focus on when your making your descision is that it is made of a durable material and won't break apart.
Balls
For dogs you can purchase all sizes of balls, this type of activity typically requires human interaction as your dog will quickly loose interest if the ball isn't being actively thrown for it to chase.