Belly Button Piercing
You might not expect the torso to be a decorative place, but it is a playground for jewelry artists. Why not make a light wire wrapped chain that could be worn as a long necklace, a doubled necklace, a belly chain (worn with a two-piece swimsuit), and a belt - that's 4 jewelry accessories in one, and a huge value to your customer! Let's not forget special occasions: if your daughter's prom is coming up, you could create a beautiful colored wire or silver-and-pearls corsage (worn as a brooch, or around her wrist). Decorate with real flowers, and she'll have a beautiful piece to wear at the prom, and to treasure for years afterward. If your son appreciates wire jewelry, you can wire wrap a design into a tie clip.
As a knitter myself, I can vouch that knitters love to fasten shawls and sweaters with handmade shawl pins - a quick search on Etsy for "shawl pin" will inspire you in no time. (Bonus: Many shawl pins can double as hair accessories!)