One large category of legal need is working with the Federal Veterans Administration (VA).
"The U.S. Court of Veterans Appeals (now "U.S. Court of Appeals for Veterans Claims") asked Congress to reallocate part of the Court’s own budget for representation for needy claimants. A consortium of four organizations received a grant to operate a pro bono programto recruit attorneys willing to volunteer to represent needy individuals at the Court. See:
Meanwhile, USAToday reports a multitude of efforts to help with these claims. Are they pro bono or in expectation of fee-on-success? Either way, it's noteworthy: