The Galaxy Note 5 and Galaxy S6 edge+ come with an official keyboard cover from Samsung, but this case isn't available for the Galaxy S6 and S6 edge. If you're looking for an alternative, One2Touch – a company specializing in NFC solutions – has released a keyboard case for the original S6 lineup. This case is a regular flip case that incorporates a full QWERTY keyboard on the flap that covers the screen.
The case is called SlimType, and the keyboard gets laid out in landscape mode when the case is open. In addition to all the letters of the alphabet, the keyboard has numerous alternate functions that can be accessed using the Function key and also has a key dedicated to emoji. The case has NFC, so you can start pairing it to your S6 or S6 edge as soon as you put the phone inside (making the back of the phone and the NFC chip in the case come together, which is what is needed to initiate the connection.)
Oddly, One2Touch says the SlimType case doesn't need batteries, which might be because NFC-enabled devices use very low power and the keyboard is, after all, simply a device for text input. Of course, the biggest concern is whether it will be easy to type on a QWERTY keyboard that's not very wide, and also the fact that you won't be able to keep the device and keyboard in your hand and will need to lay down your phone on a flat surface to be able to type.
It's an interesting case though, and some folks are likely to find some use for the thing. The SlimType is available for pre-order from One2Touch's website in Black Sapphire, Cherry Red and White Pearly color options. A price isn't mentioned, though Android Authority says the SlimType case will cost $39 for a limited time after launch.