Mini-STX
http://www.pcworld.com/article/2975764/components/intel-unveils-ultra-tiny-fully-upgradable-5x5-mini-pc-motherboards.html
http://www.intel.com/content/www/us/en/technology-provider/products-and-solutions/desktop/mini-stx-for-mini-pcs.html
http://www.asrock.com/mb/Intel/H110M-STX/
https://www.asrock.com/nettop/AMD/DeskMini%20A300%20Series/ (AMD AM4)
https://www.gigabyte.com/Motherboard/GA-H110MSTX-HD3-rev-10#ov