Finally, home screen widgets in iOS! (Look a lot like Live Tiles from Windows 8).
A new Translate app that allows you to communicate with different languages (like the Conversation mode in Google Translate)
You can now pin chats (just like in the app you're using) and view inline replies (like in this app).
CarKey allows you to tap your supported car's door with your iPhone to unlock it! And, you can share keys with friends through iMessage!
App Clips allowing you to quickly install a stripped down version of a supported app just by tapping an NFC tag, from various other apps or scan App Clip codes! (Like Google Play Instant Apps)
Compact call interface for calls and a new Spotlight-like Search interface on iPad!
A new Scribble feature allowing you to automatically convert handwriting to text (like in the Apple Newton and Windows Tablet Edition) and drawn shapes to actual shapes (like in S Note).
New Chronograph watchface with a tachometer and a huge complication on the Large watchface.
Watchfaces can now be shared on iMessage and social media, and downloaded from websites and apps.
Sleep tracking and Wind Down mode for iOS and watchOS, to help with sleep.
You can now upgrade a temporary Sign in with Apple account to use your Apple ID instead, and apps will have to ask you to track you across apps and websites.
Adaptive lighting adjusts smart bulb color temperatures throughout the day, and face recognition in cameras will let you know who's at the door.