AllThingsWorn.com is a used underwear marketplace where sellers can sell dirty panties, used nylons, old shoes, clothes, naughty extras and digital XXX content.

PantyDeal.com is a huge used panty marketplace with over 1 million women of all shapes and sizes selling used panties in all colors. Easy and anonymous.

SofiaGray.com is a huge international marketplace that specializes in selling second-hand panties, adult toys, socks and other second-hand clothing, as well as free high-resolution photo and video content.

KanojoToys.com/used-panties offers a vivid selection of second-hand Japanese panties. But they are expensive, and there is no way to verify whether the panties have actually been worn.