The University of Minnesota provides a page with links to examples of data management plans written for a variety of funding agencies across a variety of disciplines.
DataOne provides four examples of general data management plans written for the National Science Foundation. (The links are at the bottom of the page).
The DMP Tool not only walks you through the process of creating a ready-to-use plan designed for specific funding agencies; they also have a link to a sample plan created using the tool.
UC San Diegohas a collection of successful data management plans submitted by their researchers.
MIT guidelines and examples of data management plans for researchers.