InkyPaw.com and GreetingCardUniverse.com sell sympathy cards to give to people who have lost a dog. BlueMountain.com offers free printable sympathy cards for the death of any kind of pet, including a dog.
InkyPaw.com offers several different sympathy cards for the death of a dog, many of which feature photographs or illustrations of dogs. It also offers cards that are in the form of booklets about doggy heaven. GreetingCardUniverse.com offers a range of different sympathy cards for the death of a dog, including cards with sketches or watercolor paintings of dogs and photographs of real dogs, covering a wide array of different breeds. Some of its cards are specifically addressed to owners who have lost a service dog or who have lost their dog to a terminal illness.