Hi, all!
Here are the button necklaces I have, as promised.
this is just a plain one. One of my niece's first attempts. I liked her color choice.

closeup:

this one was a cooperative effort. I did the big bottom, and my sister-in-law did the "lace" part:

Oh! the flat things are the buttons, we combined it with beads. I use two strands of thread. two through the beads, but through the buttons through diagonal holes.
Here we used beads, but grouped the buttons to look like beads.

This is the one my friends like the best. Actually, I get so many requests for this one, and it is the easiest to do. I thread all the buttons on my crochet ball. Then you do a chain stitch group, slide a button, repeat. This one is for my jeans. I did 5 stitches slid a button, throughout. You do this until you have 12 feet in length. You could make it shorter or longer, of course.

my friends like it as a bracelet, too:

So far I've been asked to do it with black crochet yarn and gold metallic yarn crocheted together. Then assorted metallic/brass buttons and a random number of stitches between them.
Another friend wanted all stretchy metallic elastic and black buttons. Another friend asked for nylon thread, so they looked like they are "floating."
It takes maybe an evening or two.
I'm ready to try your knotted necklace, and see what I come up with. Yours is lacier looking, less chunky.
This will be fun . . .