I’ve gone through my collection of knitted doll patterns and bookmarks and can’t find one for a knotty style doll.
You could use one of the already mentioned patterns for the head - or this one below for a basic body/head and then knit a square/rectangle for the rest of it. Reduce the stitches at the corners and knit a small band of a few stitches to create the knot. I think that’s the way I would do it.
http://weefolkart.com/content/basic-knit-doll-6-sizes
You could always do a cloth piece under the knitted head piece so that you can get the waldorf face shaping (plenty of instructions for these online and easy to do).
You’ve given me an idea now to do something similar for gifts for new babies 