This is something that I stumbled upon a few minutes ago. I was unaware of a gesture that allows us to switch tabs in Safari.. until now. I know that we can pinch a tab in Safari to zoom out and see all open tabs. However, if you pinch just enough so that you can see the edges of adjacent tabs, you can then hold the pinch there, before the full zoom out, and swipe sideways to move to the next tab. I'm unsure of which iOS version first allowed this but I am running iOS 8.3 on an iPad Air 2 and this gesture works perfectly to switch tabs.