At the bottom of the "Supported Motherboards" page you'll see a listing of boards with headings like "2014W22." That list is automatically generated using boot logs that are uploaded by people who are actively using and testing the boards. (Unfortunately the links to the logs don't work because gitweb is disabled at the moment).

The Asus F2A85-M is for AMD chips and would be a great choice for a desktop board. There's even a nice wiki page for it here: http://www.coreboot.org/Board:asus/f2a85-m

There are a couple laptops listed on there as well. I haven't personally tried the HP Pavilion m6-1035dx, but it uses an AMD chip.

There are also some ARM-based Chromebooks on the market; The Samsung Chromebook 2 went on sale recently and sports some nice hardware. That particular one uses u-boot instead of coreboot, but the firmware is open source and there are no AMT-like shenanigans.

HTH!