This color wheel is awesome. Just choose a color on the wheel itself by dragging around the little circle, and then you can find the colors that are complementary, split complementary, etc. You can even go lighter (tints) and darker (shades) or type in a hex code. It’s fun for designing, planning, or just playing.
Because this year’s WAL in the Ravelry tapestry group is about the color wheel, I organized my cotton embroidery threads as closely as I could. Some colors only have one or two shades, but I’m learning as I go so it doesn’t matter all that much.
Design Seeds is a wonderful resource for anyone who needs some color inspiration. I like to imagine how colors combine, especially with something like inkle weaving where the warp-faced weaving is not diluted at all by weft colors.
Take a look here: http://www.design-seeds.com/.