Devices

All my devices are accounted for that should be controlled my internet at some point in the day. However I have 2 that I had to pause because I do not know what they are. And since all my other devices are accounted for I would like to delete them but I can’t cuz it says it is still connected and that I need to disconnect them in preset to delete them. Idk how to do this if I don’t know what device it is. This needs to be solved. I should be able to delete devices off my internet even if they are connected.