FreeBSD server - certified compatible hardware?

Solution 1:

Pretty much any piece of server hardware will work fine with FreeBSD - I've used Dell hardware with no problem, as well as several SuperMicro variants (IronSystems is the one I deal with most frequently, though they don't "certify" hardware for compatibility).

If you must have "certified" hardware and don't want to wade through the HCL I would recommend IXSystems - Their equipment is specifically built & tested for compatibility with FreeBSD, and they're fairly substantial supporters of the FreeBSD Foundation so they're invested (in both the monetary and moral sense) in the success of the FreeBSD operating system.

Solution 2:

FreeBSD doesn't have a certification program, so you wont find that specifically. There are system builders who build supported systems however; notably iXsystems.