Swipe sideways directly on the home indicator to switch between recent apps. There's no need to invoke the app switcher for this. (thanks Eugen)
Tap on the status bar at the top of the screen to scroll lists back to the top. This is especially fun in Photos, where you might have years or decades worth of photos (tapping on the tab bar at the bottom brings you back down 😉)
Current iOS is very gesture-driven. Navigating back a screen can usually be done by swiping right from the left edge. Modal views and large media displays can often be dismissed by swiping down.
Accidentally closed a tab? No worries, just press and hold the new tab button + in the tab overview to reopen recently closed tabs.
If you're looking to close tabs very quickly, hold the tab-overview button or the done button in the tab overview to be prompted for closing all tabs.
Delete incorrect input by swiping on the display.
US addresses have the house number up front, many other countries don't. But you can still enter the number first to use the autocompletion without it immediately triggering a search for the incomplete query. E.g. type "19 Rothenbu" to use the autocompletion to search for "Rothenburger Straße 19".
Cropping screenshots snaps to view boundaries.
3D Touch can not just be used to move the cursor, but by pressing harder you can also select ranges or, by pressing harder yet again, select entire sentences.
Select text on non-3D-Touch devices by using a second finger (thanks Martin).
Camera can scan QR codes directly, don't install 3rd party apps for this.
- Tap with 3 fingers to open Copy-Paste-Menue
- Swipe left with 3 fingers to Undo
- Swipe right with 3 fingers to Redo
- Pinch in with 3 fingers to Copy
- Pinch out with 3 fingers to Paste
- Double pinch in with 3 Fingers to Cut