If you know what wire size you have, you will also need to work out what you need to connect to. There are many, many variations of crimp, but there are a handful of very common ones, most shown in the image. Crimps designed to fit to threaded fasteners can be simply specified by the bolt size (e.g M4/ ¼”). Others may have different names dependent on the industry and manufacturer (eg lucar, faston, ¼” blade).