LED Flash for Alerts
Once upon a time, there was a family of devices called BlackBerry phones. Some of these phones featured a notification system that had its LED flash every time an alert came in. If, for some reason, you want that functionality on your iPhone, there’s actually a setting for that.
Just go to Settings > General > Accessibility and navigate down to LED Flash for Alerts. When it’s enabled, your iPhone’s camera flash will light up whenever you get an alert. That can be useful if you don’t want vibrations or sound but would still like to stay on top of your notifications. Just be forewarned that the flash is fairly bright.