I just published my first open source project, CardSliderView for iOS.
It's the UI element from my iOS app StorySkeleton.
StorySkeleton imitates a deck of cards. It didn't take long to realize that while UIPageViewController has the exact behavior I wanted, it doesn't actually allow you to change the transition style. (Well, it does, but there's only one transition style.)
The transition style I wanted was for each page to be completely rigid, like a card, with no bending animation.
So that's the intention of CardSliderView. The idea behind CardSliderView is that you've got a deck of cards, and want to flip through them naturally.
As you swipe from right to left, the next card in your deck comes on screen, and passes on top of the current card. When you swipe from left to right, the current card pushes off-screen to the right and reveals the previous card sitting underneath it.
Check out the StorySkeleton website for a video of this concept in action.
If you're a developer, please let me know what you think!