Ken Tanaka of Wish4Fish presents a short but useful tutorial on creating a simple DIY dubbing brush and magnet tool. You can find everything you need either at the dollar store or the craft store. Materials that you will need are velcro, magnet tape (if you have a stronger neodymium, use it), popsicle stick, sand paper, glue and cutting tools. The magnet tape can be on the weak side, but there are a number of inexpensive magnets available on Ebay or Amazon that will really help out on the fly tying desk.
A friend of mine made a set of dubbing brush tools as part of a fly swap years ago, and I’ve gotten quite a bit of use out of them over the years. They didn’t have the magnet component, but it would be quite useful as I employ magnets on my tying desk in a variety of different ways.