There are multiple resources to find free old stock footage that you can use in your documentary or music videos. Some popular resources are The US National Archive, Internet Archive, The Public Domain Review, British Pathé Reuters, and Getty Images: Editorial and Archival Videos, and Wikimedia Commons. As these are public domains, you can get free vintage footage without copyright claims.
Once you have downloaded the free vintage footage, we recommend you free vintage editing software Filmora to add nostalgic feel to these footages.