TFS (Microsoft Team Foundation Server) does not come up an addon that allow to add file directly from the folder. But you can do that same in Visual Studio.
Start Visual Studio, go to Team Explorer (you do not need to open any project). On the top drop down, click home. Then click the link on the top “Source Control Explorer”. Browse to the folder where the file exists. Right click on free space and click “Add items of Folder”. A dialog will show up. This will show all those files which are not check in. Select the files and click ok. Do not forget to commit the changes to TFS.