I've used a mirror and a flashlight..but that's more cuz i'm so damn fat i can't get to where I want to see what i want. I've never seen a magnet and have had one chief judge state in no un-certain terms that magnets won't be used. Never a magnifying glass, although for something like the key number on the pop out it would be handy ( i still won't use one). tape measure? not even sure where it would be used..but have never seen one. I've judged undercarriage 4 times, green bay, madison, dearborn, grand rapids and not seen any thing except flashlights, RGnJS, and pencil and paper used. but I may have been under a car...fwiw,jm