I just did a Google search and could not find Rustoleum here in Australia. I'm sure there are equivalent products.
For anything outdoors, I use zinc-rich paint, 2 coats followed by an enamel, 2 coats. For indoors, anything that bonds well to the base metal. Since I have more experience with automotive paints than industrial paints, I tend to use those products, depending on the finish required. For industrial tools, today I would look for something resistant to cutting fluids and oil, which is what I did not do with my lathe resto 35 years ago!
Thanks for that info.