Meet the Pairable KEY: a compact device you can attach to your valuable items to keep track of them. You can just ring your KEY to find your devices. The device also lets you remotely control your phone and IFTTT devices. Since it has a motion detector, you get notified if your valuable items are moved.
With the KEY, you are going to have an easier time finding your phone. It has a temperature sensor and a range of over 100 feet. The battery life lasts up to a year. Sets you back under $40.