As many of your know, I don't recommend or sell anything that is not the very best for its purpose. I recommend the following two threads of YLI's, because they are simply the very BEST threads in the market. I only use the very best @ the best value for money! Why not?
The silk threads starting with "S-" are the best for needle turn applique, not because it is silk. It is because it is the thinnest thread in the world (the second thinnest is almost twice the thickness!). The finest thread makes your blind stitch truly invisible (Liuxin's Applique book explains to you the science of matching the thickness of thread and width of seams). It is also the BEST for whipstitch piecing in double threads - fine and soft.
The cotton threads starting with letter "C-" are the best for extra fine and even hand quilting stitches with its unique stiffness. Scroll down the last page for the quilting threads.