Here is the amber I ended up buying, and it was a fabulous pick!
What else might a witch wear? I'm focused on vintage right now. Vintage is greener! All the resources to make the clothing have already been used. Hopefully, the piece has been worn & loved by someone prior to you, so it's recycling at its best. Here are some vintage embroidered dresses from Mexico. All are lurking in my Etsy favorites right now, but I have not moved in for the kill yet.
Comfort & prettiness come to mind with this purple piece. Not terribly pricey, at $26 I'm thinking that the embroidery is done by machine. However, it looks pretty darn good!
I love this long-sleeved one but, of course, it's $75. If you run round in bare feet like the model, it looks like a nightgown, though. More money, but definitely hand embroidered, with some beautiful smocking. This Etsy seller, Honeywood Vintage, has a shop full of this type of dress, so have a look if this appeals.
Two pics of the final dress:
A brighter yellow at a nice price, $25. It's a fiesta dress! Imagine it after you have laundered & ironed it!