I think nothing like this exists as block libraries are not that taxing on a network, plus if the "cloud" is down you are kind of SOL when it comes to obtaining the files. The (3) main providers each have had complete outages within the past year, with MS just last week having their Azure network down.
I don't use the design center but from what I do know, you essentially go into drawings and pull the blocks you want. Unless you had each block as it's own DWG file, I don't know of a way to "track" each block you pull down. One way to track which files are accessed look into a 3rd party windows or *nix auditing program which can track what users pull what files.