The Speck CandyShell Card case fits all the iPhone 6 models, include the iPhone 6s Plus that was used in the review.
Holding up two 3 cards, it's also capable of securely holding in a single card due to their friction locking system. Don't limit yourself to just cards as cash, receipts, or anything else flat will work as well!
Unfortunately, like most CandyShells, the glossy plastic back is still plagued with the scratching issue which becomes prominent quickly after you start using it.
Photos coming shortly!