Are they copyrighted? Because if they are, it doesn’t matter if it’s free, but you can get sued (for using a copyrighted background).
For the rest, on this forum you’ve some artists who’d like to make some free backgrounds for you (don’t forget to credit them).
And maybe episodelife.com has some holiday-backgrounds.
For a Christmas story I recommend:
You can either checkout or request Marysol.Episode to make you whatever you want. Her backgrounds and overlays are so amazing and just so cute. I really recommend you to check it out girly. Everytime I see it, makes me so upset because I’m such a lacking person who can never finish writing her own stories
Best of luck with your story!
I have a drive which contains a christmas cabin set. It is paid access, but only a small one off payment for permanent useage. If you’d like to see more of the content, you can see my thread here, or go to my Instagram @ cheyara_writes58