My most favorite designer I like to test for is Yarn over New York. https://yarnovernewyork.wordpress.com/
I was very happy to participate in the test knit for the Ghost Ranch cowl. I love the was the slipped stitches combined the colors and gave the impression of a herringbone design. The cowl pattern was knit in the round with US Size 3 (3.25mm) needles, and have to be careful to use the shortest circular needles you can.
I used two color combinations for each cowl. The cowl on the left was made with Debbie Bliss Rialto 4 ply in forest green, yellow green, and cream colorways. Although the colors are neutral, the pattern made them really pop. The cowl on the left was made with Rowan Super Fine Merino 4 ply in Sky, Lilac, and Fresh. These contrasting colors gave me great look as well.
I look forward to the opportunity to test again for this designer