So projects which are actually not secret. DARPA and the like maintain lists of such projects on their websites[0] and probably also have lists of past projects somewhere. Only one currently active and disclosed AI project but I am sure they have had many others. And the various private think tank/pure research organization websites would be good to dig through, the bulk of this stuff might as well be secret consider how little anyone outside of the respective fields pay attention to it, looks like The Max Planck Institute has a department for intelligent systems [1].
0: https://www.darpa.mil/work-with-us/what-is-our-current-inves...