In Visual Studio 2015 I could use the TFS Power Tools and then do a \"Find by Status\" to get a list of all checked out files and who has them checked out.
Does anyone
Actually, the "Find by Status" feature only works for Server workspace. If you're using Local workspace, it doesn't show anything.
As a workaround, maybe you could use the tf status command instead, it displays information about pending changes to files and folders.
Or you could use TFS API, here is an example: http://geekswithblogs.net/TarunArora/archive/2011/07/16/tfs-2010-sdk-get-list-of-user-workspaces-and-checked.aspx.