It would be really useful to have some sort of overview of the Steam folder that breaks down the disk usage of games that are and aren't installed and can remove folders that even when uninstalled are using too much space. The reason I say this is because, over the years, folders tend to build up and use lots of space, even when there is no hope of you ever playing the game again. Using a third party app, I found one game that left 20GB in Common when uninstalled!