I bought these shelves from IKEA for yarn storage. They are called Bitrade (2 units) 26 3/4 x 53 1/8" & 49 lbs. Model #21348. Priced at around $29.99 each. Thought that was a great price and I am pleased with their sturdiness and fairly easy to put together as long as you read the directions and have a helper. I love these shelves.
This is my solution for thread and project organization. I had a couple hanging files that I cut and hole punched, labeled the holes (with pencil so I can change it later), popped them into this hanging file milk crate.