Each of these sets by Tulip includes various sizes of metal needles, perfect for Sashiko stitching.

Big Eye Set includes four 0.84mm x 51.5mm straight thin needles.

Assorted Long Set includes 2 each of size 1.02mm x 66.7mm, 0.97 x 44.5mm and 0.84mm x 51.5mm. This set is made with a big needle eye and is designed to pass through fabric smoothly

Sashiko samplers are available here and floss is available here.