mCookie by Microduino Studio (2015)
mCookie is the latest project from Microduino Studio. Their goal is to make all the different sensors and circuits into a unified stackable design. Therefore it makes the prototyping process much easier and cheaper.
All mCookie boards are Arduino-compatible. Makers can write their own programs in the Arduino IDE and upload their code to the hardware via USB. It dramatically decreases the size and cost of design prototyping, improves flexibility of Arduino-compatible boards, and enhances the user experience of building IoT projects. You can learn more about this interesting project in their Kickstarter page.