This blog post is 90% SQL server and 10% Power BI, so if you are not into SQL Server (or relational databases in general) this might not apply to you. That being said, this blog post explains how to record the size of all tables in the server, and how to measure which tables are being used without enabling query-logging which can bring your server to a halt (or at least so I’ve been told by the DBA).
Some context, in one of my clients they do have most of the data that they manage in a SQL server with ODS replications of operational databases and a data warehouse where all serious reporting should be based. In that sense they have things pretty much sorted out if we compare them with companies that still do critical reporting based on excel files on a SharePoint. Yet, even having a very expensive server we often run into problems and space is always a problem. So we figured to do something about it.