DigiLux Lets You Use Fingerprint Gestures to Control Brightness (Android 8.0+)
There are a few applications out there that let you remap fingerprint gestures to various tasks and shortcuts. If you have Android 8.0+ though, DigiLux from XDA Member youtube10 will let you use gestures from the fingerprint sensor to adjust the brightness of your display. Along with letting you set fingerprint gestures to control the screen brightness, it also has options for setting gestures to actions in case you’re used to them from other apps. Most of the application is free but it has a couple of premium features including a way to pick the slider colors based on your wallpaper, and an option to add a dimmer so you can lower the brightness even further.
See http://bit.ly/2zDHh3m where there is also a link to download the app from the official Android app store.