You SCORED Big Time.... The zigzag attachment is worth almost $50
here is a link that shows a couple of the parts that you had questions about...
http://www.april1930s.com/html/singe...zag_attac.html
the attachment that is the top far right is THE BINDER... used to apply commercial binding as well as self-fabric bias..
Top left attachment is the EDGE STITCHER - when stitching must be kept accurately on extreme edge of a piece of material. The slots, numbered from 1 -5 serve as guides for sewing together laces, insertions and embroideries, sewing in position hemmed or folded edges, piping or sewing flat braid to a garment 9 singer featherweight 221K owners' manual)