The New York Public library has put online its collection of color military plates. Most are hand colored block prints. The collection of Mexican Uniforms 1826 – 1906 could come in handy as a painting guide for the Texas Rebellion and the US – Mexican War, as well as the Maximilian period.
The New York Public Library’s digital holdings have an amazing collection of color plates of British uniforms from 1066 – 1900. These are great painting guides.
The Jackson Gamers have a very detailed guide to gaming the Russian Civil War.
In N scale here are some free paper models of the tracks of Chicago’s famous “L”.
Terragenesis has a nice article on casting bunkers in plaster from chocolate boxes.