If you’re good at something, charge for it, right? Then what would you say if someone offered you a base of 1500 4K clips to use for absolutely free? But wait, there’s more: you can use the clips for commercial purposes for free as well. In a text at fstoppers.com, Chelsey Rogers writes about Mitch Martinez, a DP who decided to share his wealth with the filmmaking community (quote via fstoppers.com):
I'm here to help. It's very rewarding to contribute to the film community, the entertainment of people, and even educational applications. It's kind of a "day off" type of thing.
The library contains more than 1500 clips, according to info at mitchmartinez.com, these are h264 encoded mp4 format. Clips cost you nothing; they are royalty free. There is only one ‘but’ - if you’d like to use them in a commercial project, you’ll have to complete a form ‘to ensure proper paperwork for use of the stock footage are in place for your project.’ The clips remain free nonetheless. Basically, what you cannot do is resell the clips or present them as your own.