I know I run into these all the time. I think some of these are developmental boards for game kits, while others like people mentioned a specific computer part. Their is a gamedev system I keep seeing for sale, but it is for NES/MSX type games but is not of those types.
I keep asking myself that question as well. What are those things. If you was a programmer, who would play with dev kits ( to aid programmers, and fun projects for them ) then you would know more.