I ordered a couple items from Cheap Joes.
I got the Brush Tubz to protect watercolor brushes in my bag. If I don’t want to carry a big brush case, this lets me carry 2 or 3 brushes in a way that protects the brush but doesn’t add bulk. The soft plastic lid is flexible. Insert the brush handle through it and then put the tube over the brush tip. Works great! For under $5 you get a pack of 12 tubes.
The other item is a strap for tools. It’s less successful. In order to stay over a sketchbook, the book has to be a minimum of 9-10 inches across. If it is that big, then the tools do stay in the elastic sleeves well. It could be a good way to carry a few tools and the book without toting an entire bag. Only one of my sketchbooks is large enough to fit it, tough. I’m not sure how much I would use this.