Updated: Dec 3, 2022
Rumbl from West Paw: a tough rubber-like material that’s pretty quiet when rolled around. I give Molly hers in her crate so it doesn't get stuck under the furniture.
Snuffle mat: Be sure to supervise this activity. You can find many vendors selling these on Etsy (some of which are works of art - I could get addicted to collecting them), or you can make one yourself.
Kong Wobbler: A hard plastic toy that stands back up every time the dog knocks it over. It can be a more challenging toy. Fill it full until your dog learns how to work it, then you can add a measured amount.
Kong Gyro: A more challenging toy. Fill it full until your dog learns how to work it, and supervise. It is hard plastic but not totally chew proof!
Here is a video of my friend’s foster dog enjoying this toy.
There are many more options out there! Here's a link to a review of other options, plus some DIY suggestions.