Years ago, there were not only library card catalogs but the cards within them were handwritten. Written not with the hen scratching that characterizes my (and probably your) handwriting but with a beautiful, legible, and, as it turns out, standard penmanship.
Librarians of the day settled on a standard way of writing the cards called Library Hand. If you follow the link, you will find several examples using both printing and long hand. These days everything is computerized—or at the very least the cards are printed—but it’s fun to read about how librarians struggled to find a standard way of writing for the cards. If nothing else, you can enjoy the examples of the art.