Goughnuts-
Floatable, Rollable, Chewable, Smellable, Indestructable - this toy is a must have for all dog lovers.
See a video of Irvine loving this toy.

Nylabone-
This is a safe way for your dog to conquer its urge to chew.

Tug Toys-
These are great to incorporate in your training. If you feel your dog is getting overwhelmed with training just take a break and whip this toy out for a quick break.

Kongs-
Dogs love these but make sure they are supervised as some dogs will chew these through and pieces break off. You could keep your dog occupied for a bit by filling the Kong with peanut butter or small dog milkbones.

Ice-
Dogs love ice and you can make ice toys. Find some old containers and fill them with water, place some dog kibble inside the water and freeze containers. Dogs will enjoy crunching on these.

Toys to avoid-
Latex squeaky toys
Cow or horse hooves
Pig ears
Rawhide bones
Real bones (e.g. knuckle bones)
Most fabric or stuffed toys

It is best not to leave your dog unattended with these toys, but can be great toys to interact with your dog:

Frisbees or flying discs
Tennis balls
Rope toys are great for tug games, but unattended a dog can gnaw, shred and possibly choke on the rope remnants.