The walking foot is one I can't live without. #20 for doing buttonhole applique and sewing on Velcro. #6 is the same thing as a #20, but it has a center bar with a hole in the center, so you can zig-zag over a crochet thread for gathering (works better than the #16 gathering foot). Sometimes I wish I had a #2 (overlock), which keeps the raw edge from collapsing as you finish it. And the #18 (button sew on) is one I really want to get. When you've got 12 buttons on a tablerunner, that's the way to go!