Separately, I have naturally dyed 3 different kinds of embroidery threads using a number of natural dyes, including: Cochineal, Quebracho Red, Madder, Goldenrod, Osage, Weld, Indigo, Logwood, Cutch, Tea, etc.
The 3 different kinds of embroidery threads have different qualities: 100% Cotton DMC, pliable thread (sheen surface), 100% Cotton Sashiko thread (not pliable & mat surface), and a Linen & Cotton Blended slubby thread (organic surface). Below are 2 videos covering the naturally dyed embroidery threads and a final gathering of materials.
You can learn how to naturally dye fibers in my online courses, which covers fiber preparation, dye preparation & modification, and dyeing. Check my site for release dates: https://learn.sarahtremaine.com