Here is a handy tool that helps you keep an eye on your valuable items. The Pixie Lost Item Finder comes with a tag that you can attach to the back of your phone. The other tag is used to track your other important items. It has a range of 30 feet indoors and 100 feet outdoors.
Pixie uses your phone to track where your items are and guides you to them step by step. More info is available here.