For the last couple of years, we've been tagging our bags and backpacks and wallets with Bluetooth Low Energy (BLE) trackers from TrackR.
Like the other BLE trackers, TrackR devices have been getting smaller -- the latest is the size of a large coin -- and they form a crowd-sourced anonymous network, so if the bag I leave behind is near your tracker, I can see where it is on the smartphone app and go back for it (assuming I missed the alarm as I walked away from it). One big advantage of TrackR over the other devices is the replaceable battery. The other is that it has an SDK, the Works with TrackR program, so it can be part of a bigger system.
TrackR is working on that itself with integration with the Amazon Echo; ask Alexa (from your phone if you're not next to your Echo) "where are my keys?" and as long as you've tagged the TrackR on your keys as tracking your keys and put the $39 TrackR Atlas gateway in your kitchen, Alexa replies "your keys are in the kitchen".
You can even draw out a floor plan of your house so you can see where all your tracked devices have ended up.
Some fashion brands are also signing up; Mezzi and Royce Leather are building TrackR into wallets. If it's your pen you're looking for, you might not bother putting a tracker on that, even if it's an expensive pen, because something dangling off the end of your pen gets irritating very quickly. Cross is building TrackR technology into its Peerless pens directly, so you can keep tabs on your $600 pen (I'd love to see Microsoft put it into the Surface pens, which already have Bluetooth and a battery).
Tagging your camera bag or your laptop bag is such a no-brainer that HP has done a deal with TrackR and is putting tags on its new Executive line of laptop bags.
Interestingly, these have both a pocket to zip the TrackR into - because if it's dangling on the outside a thief could just unclip it and drop it in a bin as they head off with your bag - and an RFID-blocking pocket (lined with a metal mesh to make a tiny Faraday cage) to stop your NFC credit cards or the fob that gets your into the office getting scanned by a pickpocket. Going for a job interview or a confidential meeting? You might want to move the TrackR into that pocket for the afternoon too.
Putting tracking tags on laptops at scale gets interesting for business, and you can tag anything; this is a mobile asset management system that can cover your office and the world outside it. You can see your printers on the network, but sometimes it's handy to know when they're not in the room you expect them to be in and if someone borrows a 4k monitor from a colleague's desk while they're on holiday, that's good to know as well.
TrackR has a good head start here, but more widely, the idea of BLE beacons on devices and covering indoor locations is going to be very useful for indoor location.
Future generations, when flexible batteries and printed electronics let you put a BLE beacon in a sticker, will let us track smaller items, but for now, think about how useful it could be to make the devices you carry around a bit smarter about where they are.