This app was mentioned in 3 comments, with an average of 2.67 upvotes
This app is amazing. Can even make gifs out of the burst photos. No shutter sound, 10-30 photos/sec, not blurry, infinite focus. I use it on the 10/sec setting and can be walking by with high res shots. Works amazing in daylight, inside buildings doesn't work as well, but still is great.
The Android app store has the generic Fast Burst Camera app, Samsung phones tout their own app that does similar things, and I wouldn't be surprised if iOS devices had a similar app.
I like Fast Burst Camera. It's pretty remedial, but boy does it take pictures fast. https://play.google.com/store/apps/details?id=com.spritefish.fastburstcamera