There are some remnants of a disabled alarm system, could these be door sensors by any chance. If they, is there a way to access them, because when I add an ip address, and try to ping them I get no response.
Could it be an IP camera? Google the vendor name it may give you some ideas. I’ve had some of my devices show up with Mac ID only so I just delete them from known devices and on the next reboot they often appear with a proper name. I use ASUSWRT device tracker so it’s always checking for devices… Also I went through the client ID list in my router and properly named any unidentified devices there it helped me to narrow down what was what.
I’m using the nmap and bluetooth trackers. I get the mailman and the Prime Now delivery people showing up on mine all the time. I just set “track: false” and forget about them. It could be something like that for you too if you are using either or both of those trackers.