I have gotten good use out of these dog bone cookie cutters, both for making dog treats for dogs and dog treats for people.

https://www.amazon.com/dp/B0B3DKJF8K

You can use any type of cookie mix you like. But if you want a little extra authenticity, these peanut butter dog treats are loved by dogs and fully edible for people, if a little bit bland.

https://www.thecookierookie.com/pb-dog-treats/