>>2
I know the RYF webpage. The Raptor Systems are impressive and they're the only computers I know that can boot for sure without proprietary code. I'd certainly recommend them to business owners but I'm looking for something for my own modest use and I don't have that kind of budget. I've alow followed Carefully coreboot and Libreboot hardware compatibility throughout the years but I'm wary of second hand electronics.
I'm more interested in the i.MX6 platform.
https://www.fsf.org/resources/hw/single-board-computers
This page doesn't cite any single model and there are plenty. (It's actually a good thing because if any one model got official endorsement from FSF it would be rebranded TechnoSaveThePlanet or RedditPenguin and its price would go from $40 to $400 even when sold from Chinese retailers)