1. Make your speakers louder.
Go to Settings > Music > EQ, and check "Late Night." That'll give your iPhone's speakers a little extra punch. Try it with music playing and hear the difference for yourself!
2. Change your display to grayscale — and ~maybe~ become less addicted to your phone.
This is an accessibility feature for people who have difficulty seeing certain objects on their screen due to colorblindness, but some people claim that turning off the bright colors on your phone has the added effect of making you less addicted to using it. The theory is that basically every app is designed with just the right combination of colors and notifications to get you to use them (it's basically impossible not to tap on something that has a big red notification number on it, right?), so taking away the colors will wean you off of them.
You can apply this filter under Settings > General > Accessibility > Display Accommodations > Color Filters. There are also options for other various types of colorblindness.
If you want to be able to switch back and forth quickly, you can go to Settings > General > Accessibility > Accessibility Shortcut > Color Filters and activate the shortcut. After that, you'll be able to click the home button three times to turn the filter on or off.
3. Search your photos based on the objects that are in the photos.
4. Change the brightness of your flashlight.
5. Take a shortcut to important menus like Cellular Data and Battery.
6. Limit the amount of space your music can take up by automatically deleting songs you don't listen to.
7. Find out where you parked your damn car.
8. Use your phone as a level to hang pictures.
9. Erase just one number in the Calculator app.
10. Unlock your phone without pressing the home button.
11. Make your own shortcuts for emojis.
12. Set a timer to stop your music from playing after a set amount of time.
13. 3D-touch the keyboard to move the cursor around in Messages.
14. Pause, play, rewind, fast-forward, and skip songs using just your wired earbuds.
15. Get less blue light from your screen to ~allegedly~ help you sleep.
The scientific consensus isn't exactly clear on whether less blue light from your phone will help you sleep, but it can't hurt to try. You can activate Night Shift by swiping up from the bottom of your phone and hitting the button in the Command Center, or you can go to Settings > Display & Brightness > Night Shift and schedule it to automatically turn on at a specified time.
16. Undo your typing by shaking your phone.
17. Temporarily shift all your apps down so you can reach them with one hand.
18. Use Siri to get an Uber or Lyft home.
19. Send your texts with a little extra pizzazz.
If you press and hold the Send button in Messages, you'll get a ton of options to send your texts with effects. These include effects within the text bubble, or full-screen effects like confetti, balloons, or even a shooting star.