Mike Cooper has a web page with useful information on World War Two vehicle camouflage. IIt includes text descriptions, as well as a virtual “paint chip” gallery.
Painting Guides
French Uniform Guide 1690 – 1900
Les Uniformes de l’Armee Francaise contains a series of marvelous images that will work very well as a painting guide.
British In Zululand Painting Guides
Duncan’s Colonial Modeling blog has a nice series of photos of British uniforms intended as a painting guide for the British in Zululand
Polish Uniforms 1633 – 1797
The New York Public Library’s Digital Collection has plates of Polish uniforms from 1633 to 1787.