One of the yarns I'm featuring in the shop is Shetland 2000. It was developed way before the current trend for natural and organic yarns, and is imported by my friends and mentors at Yarns International, Betty Lindsay and Bonnie Hassler. I named two of my sheep after them, by the way. It's a totally natural product, free of dyes, and comes in 9 colors. You'll find a sweater made from it, The Shetland Fern, in the new book The Natural Knitter, by Barbara Albright.
The amazingly talented knitting designer Ron Schweitzer has authored a series of books and patterns for Shetland 2000, available mostly in kits from YI. Some of them expand on the color palette, using plant dyed Shetland. This book, Postcards from Shetland, was designed by me (I'm a freelance graphic designer as well as fiber artist/yarn shop owner).
You can see all the colors in use in one sweater in Albright's earlier book Knitter's Stash, in the River Run pullover. I am not a fairisle knitter, but at some point I really want to make that one.