A lot of these concepts hail from the Open Compute Project[0] which I might have missed being mentioned in the page. ORv3[1] is a 21” rack design that exploits the fan cube law, basically - a lot less power is needed to push the same volume of air given a larger fan blade diameter. It’s a neat cooling concept I think about often.
[0]https://www.opencompute.org/projects/server
[1]https://en.wikipedia.org/wiki/Open_Rack