Plastic cube toys that you can put food into. As your dog moves the cube, bits of food fall out for your dog to eat.
Tough rubbery toys that you can fill with yummy treats for your dog to get out. These can also be filled and frozen, then given to your dog for a great 'cool' treat.
Don't forget to change your dog's toys over regularly, every two or three days. (You don't like doing the same old thing day after day for entertainment do you?)
Hide your dog's toys around the garden or use a snack trail to lead it to the toys.
Sand or dirt pit
Give your dog a specific area where they can dig, scratch or bury their things.
In warmer months
Freeze some dog food and water in a big icecream container or freezer bag. You have a big frozen cube/treat that will occupy the dog and help keep it cool.
You can make one. Use an empty cardboard box with some cat toys inside.
There is a great range of scratch poles available or make your own with some timber and carpet off-cuts.
You do not have to buy expensive toys, you can make your own. Empty decorated toilet rolls, old scrunchies, wool, and ping-pong balls make a great start. Plant some 'catnip' in the garden or as an indoor plant.