The agency that is not an example of the expansion of the power of the federal government during World War I is the American Civil Liberties Union.
The ACLU was founded in 1920 in response to the civil liberties violations that occurred during and after World War I, particularly with the Espionage Act of 1917 and the Sedition Act of 1918, which led to an increase in government overreach and suppression of dissent. In contrast, the War Industries Board, the Railroad Administration, and the Food Administration were all agencies that represented an expansion of federal government power during the war to mobilize the economy and manage resources.