I highly recommend the patterns listed on this page as a projects for gradient yarn, and usually have one or more of each as samples in my booth. I have knitted each of them, often more than once, or have collaborated with a designer who has kindly shared their knitted sample while I continue to knit at the speed of frozen molasses. ;)
Selected patterns are:
Well-written and easy to understand.
A great design to show off a long-colour-change gradient yarn.
Each pattern is owned and distributed by their respective designers or publishers. Links in this page will open a ravelry pattern page, ravelry project page, or other designer website.
The only "design" by coriand3r knits is the Moebius Cowl Seed Stitch which is more of a recipe that I wrote down in my Ravelry project notes. It's based on publicly available tutorials, and reference information from excellent online published knitting resources and knitting instructors.