One extremely sad example is the libraries of brass matrices for hot metal type --- all-too many of these were melted down, mostly to make shell casings by vari

One extremely sad example is the libraries of brass matrices for hot metal type --- all-too many of these were melted down, mostly to make shell casings by various accounts. After the war, it was necessary to re-create said type libraries, mostly as phototype though, thus ending a golden age of printing which had reigned since Gutenberg, eventually, the Linotype and Monotype machines followed this into dissolution when digital type became prevalent. While most designs were eventually remade as phototypes, and later as digital type, many of them were only imperfectly preserved, so for example, rather than all the different hot metal sizes and variations, only a single phototype master usually exists, capturing only the state of a single size (usually a larger display size).