I go through a lot of cans of fire red tremclad, just for that purpose. my favorite go to hammer which is an old stone hammer, found it on the field road without realizing i had lost it. everything is red, Lol. Even stuff i use on the john deere tractor, if it can fall off it is red.When I was a kid my dad painted all of his tools bright yellow so he could spot them when he lost them in the field. 30 years later I still see his tools and have found several of them in the field. He always seemed to leave a few on the frame of his equipment.
i haven't tried it yet, but, i was going to try some glass beads (sandblasting) on wet paint so it would reflect bright at night if headlights hit it.