I'm such a sucker for gadgets! Until a little recent research, my concept of trackers was a vague mixed-up jumble of untruths alluding to GPS devices and mysterious FBI vans.
Put simply, in the current state of development, a tracker is just a little Bluetooth chip with a speaker that can be summoned from a phone app. For example, this would let one find one's lost keys if one were on a keychain in another room.
They've undoubtedly improved since their inception a half dozen years ago. Now, they can show their last mapped location if it lies further away than Bluetooth's mere few hundred feet. Many brands have an anonymous crowd-sourced software feature that allows other users to automatically help find a tagged object if lost in a public place.
I have absolutely no need for this type of device, but I just ordered Tile Mates from Amazon Canada. Each was priced substantially less because of the four-pack deal. Tile is the present leader in North America although they may not be the best choice. In fact, I contemplated going with Chipolo which is popular in Europe as they offer more robust services free of charge. However, an order would have to be sent via international courier and take 5 to 14 days to reach Western Canada. Because of overnight delivery, I hope to start playing with my Tiles tomorrow!