I am doing research for Kanban tools which has the ability to download Work items from TFS, what i have found so far are Eylean board and UrbanTurtle. If you could post others, I would really appreciate this, but the requirements is a solid supported tools, not open source rarely updated projects.
What functionality are you looking for exactly? TFS 2013 (and TFS Online) have a Kanban board
http://msdn.microsoft.com/en-us/library/jj838789.aspx
There is some support in TFS 2012 (Post Update 1), but not sure how much they have.