Our server running Team Foundation Server 2013 ran out of storage space and I noticed there are 3 databases occupying 40GB: WSS_Config, WSS_AdminContent, WSS_Content. As I saw these are related to Sharepoint which we never use. Is it safe to drop those and uninstall Sharepoint Foundation 2013?
You are currently using SharePoint or it would not have 40gb of storage use. I would recommend that you increase the disk space on the server. Maybe you can move other things like your backup, drop folders, and such that often end up on the TFS server.