Grid-It! by Cocoon Innovations is an organizer that has a weave of elastic bands in various sizes to keep the contents of your bag neat and tidy. It’s extremely versatile with multiple configurations to secure your phone, wallet, SD cards, pens, compact camera, and more. Available in a variety of sizes and colors black, grey, blue or red.
You can see more options via Unpluggd but I like this one. It just looks like it makes sense. I just wonder if stuff will fall out.