FME Server records the job information of the jobs that have been run, and usually a system cleanup task will remove these after some time. That's great for what has recently occurred. But in the scenario that you want to find if a workspace has been used over a long period of time, then you would have been required to store this information and long periods of time. So right now, I can't tell and will need to records these details for the foreseeable future.
So I would like a new table in the FME database with an api call in front of it, that records the last date a workspace was run and maybe a couple of other fields such what ran it (e.g. an App, webhook etc) and what user. Over time this could be expanded, so it also said also recorded the last time a Server App was run, or when a token was run (especially as users often create tokens for a range of things and it is very hard for admin to confirm they are used)