There are a few options for finding copyright-free videos that you can use on YouTube:

Creative Commons videos: These are videos that have been released under a Creative Commons license, which allows you to use and share the video as long as you give credit to the original creator.

You can find Creative Commons videos by searching for "creative commons video" on a search engine or by using a site like Pexels, which has a large collection of Creative Commons videos.

Public domain videos: These are videos that are not protected by copyright because the copyright has expired or the original creator has waived their copyright.

You can find public domain videos by searching for "public domain video" on a search engine or by using a site like the Public Domain Project, which has a collection of public domain videos.

Stock videos: These are professional videos that you can purchase and use for a fee. There are many stock video websites where you can purchase stock videos, such as Shutterstock and iStock.

Your own videos: You can also create and use your own videos on YouTube. This is a good option if you want to have complete control over the content and ensure that it is copyright-free.

It's important to note that even if a video is labeled as "copyright-free" or "royalty-free," you may still need to credit the original creator or follow any other terms of use that are specified by the copyright owner.

Make sure to carefully read the terms of use for any video you use to ensure that you are using it legally.