While we can't pack "breakable items such as snow globes or glass containers" in our shoeboxes, sometimes an item may be a little delicate. I've ran into this before with say a plastic toy with some fine parts, or sunglasses that also have the risk of scratching. As I tend to pack my boxes very full, sometimes there's a little pressure built up in the box and I worry about that damaging an odd item. In the past I've often packed them right next to the soft stuffed animal as it's sure to have some give in it to protect them. Another way I address the concern is wrapping the item in something soft, and/or putting it inside a tin. Here's a couple of examples.
How do you pack items that worry you in shoeboxes?