If you have yours in jars (or boxes, or bags) sorted by color, that's the easy part. But what if you want matching buttons? Do you dig through all the blue ones trying to find buttons that match? Try this...first keep a good assortment of different sized safety pins around. When you buy buttons (or, as I do, cut them off a throwaway clothing item), place the ones that match on a safety pin. You can find safety pins in all sizes that will fit the button holes. Put the ones that match together on a safety pin and then just put them back in the container for that color buttons. Voila! No more searching for matching buttons.
Hope this helps someone (besides me) solve their button hunting! Have a blessed day!