Are you familiar with the FamilySearch Indexing Project? This is an initiative from the Church of Latter-Day Saints and via the efforts of thousands of volunteers, they are making parts of their collection freely available online at their Family Search RecordSearch & FamilySearch Beta websites.
Recently, FamilySearch announced the availability of a new collection that is available for volunteer indexing, NC Freedmen Letters from 1862-1870. Here is a sample image:
The project goal is to index every name that appears in these letters and more details can be found on the project page. If you have some free time to spare, consider registering and indexing a batch or two.