I have made and sold walker bags for many years and there are two styles that have been the best and most requested. They are the foldover style with two or three vertical pockets and the basic tote bag with an interior pocket and straps that go over the walker cross bar. Should you have any additional questions, please do not hesitate to pm me and I'd be glad to help however I can. This site has good patterns for both types:
https://hellosewing.com/wheelchair-walker-bag-patterns/