Here you have to sources for Music and Photos what are free for commercial use. You can use them on YouTube videos and still monetize them or basically any commercial distribution you make and you don’t have to pay a single penny to the creators of the content.
Now you can pimp your YouTube videos with Music and Photos and still monetize them and earn Money with it.
I use this two sources every time I make an video. Within minutes I find a matching picture or music piece and I can just download it without registration and use it ony my video. Upload it on YouTube, monetize and it’s done.