I personally consider all three of these safe chew bones for small yorkies. They are hard enough so they can't bite off a chunk.
Hartz bones
As a chew bone for your yorkie, I personally recommend the Hartz bones. They are sturdy and I have not had a problem w/ them. Please get the size that is best for your yorkie. A toy that is too small can be dangerous. I use the tiny ones for my little puppies, but for 6 months and over, I use the next size up and for the adult yorkies, I use the larger ones.
This is the Kong toy for pets
Another safe toy for your yorkie is the KONG toy. These are fun toys and your yorkie will grow to love them. It is a small red toy with a hole in it for hiding treats that will entice your yorkie to try to get it out. Some people put chicken broth in the hole and freeze it. The yorkies love this also, but remember, this can be messy. Please buy the size Kong that is recommended for your yorkie.
We all love stuffed animals. They are fun and safe for yorkies when you know what to look for and supervise your yorkie when he plays with them. They are great for fetching and for tug o war. Please be sure your stuffed toys are free of buttons or any other loose parts that can come off. When your stuffed animal gets torn, and the stuffing is starting to come out, please take it away from your yorkie immediately. Yorkies can and will swallow the stuffing and this will cause alot of trouble in their tiny systems. Also, please be careful of squeakers in these toys, as yorkies will work to remove them only to chew them up and possibly choke on them. Always be VERY careful of any strings on toys. This can get caught in their intestinal track and really cause problems.