Amazing treasury of stills and video from 75 years of Newsreel.  Low-res versions can be used freely.  Hi-res 300 dpi versions can be licensed.  I think the low-res versions are good enough for most web-uses unless you need to zoom-in on small sections.  BTW, don't go there now because the site just opened and is swamped.

Yesterday, I was looking at Hemera Photo-Objects series and got side-tracked as usual into thinking about value-added multimedia contents.  Photo-Objects is basically an image plus a mask.  There is no reason for the image and the mask to be together.  Likewise for image transforms.  In a sense these are like add-ons for an image and one could potentially search for all available add-ons given an image's URL or URI.  The same can be done with audio.  Given any audio, there are countless ways to transform it.  Also, a song doesn't have to be played in just one way or have just one lyric per language.

Only problem is that there is no infrastructure for value-added content.  There are plenty of tools to create them, but what do you do with them once you have them?  You can't find them reliably using search engines nor are there ways to buy or sell them.