Any sort of stockings, pantyhose, thighhighs, bodysuit, or other legwear featuring a vertical seam (not vertical stripes) running up the front of the legs.
Although several styles of back-seamed legwear also have a matching seam up the front, tag only the style that is visible in the image (unless both shown in the same picture).
This tag implicates seamed_legwear (learn more).