I have 3 or 4 sets of measuring spooks, including a lot of odd sizes (½ tablespoon, 2 teaspoons, 2 tablespoons, etc.) and in various shapes, including some that are oblong to fit in spice jars. I keep them all in a drawer with other kitchen gadgets (whisks, silicone spatulas, etc.) in a drawer divider/organizer.
I think magnetic measuring spoons would be a major PITA because it would take two hands to separate them to find the one you want. Might be useful if you had something to stick them to, like a refrigerator.