When I went down the rabbit hole of looking into pet trackers, the fact an iPhone needs to be nearby for AirTags to work is a problem to me, as well as the need for a SIM card in the tracker itself. I was thinking it could be nice to use a Zigbee type RF tranceiver as the range can be pretty fantastic [1] and they're very low power, and perhaps the base stations could forward messages they each received to each other to create a mesh across a neighbourhood to track far roaming cats. This wouldn't work for cats that go _really_ far (some can go several km in one day/night) but would for cats that only go a block or two. And the mesh could be used for any other item tracking needs too.

[1] https://lowpowerlab.com/forum/rf-range-antennas-rfm69-librar...