First of all, the card back took me all of 30 seconds to make.
Literally just took the logo and mirrored it. Nothing more complicated than that. The Ghibli logo is very clean and simple so I decided to stick with that.
I struggled a little more with the frame for the artwork on the front, but in the end I came up with something adorable that I'm happy with.
Oh my god. I'm so excited about the Strength card. I'm so proud of that one and I love it so much. I also managed to cover most of the main characters of the main movies, which I'm happy about. I struggled a bit with the Justice card, I really couldn't come up with something good, so I picked a picture that seemed to show balance and duality to me. I don't know, it might be a stretch, but it works well enough in my head. Also, I'll have you know that I added the reflection and ripples effect to the Wheel of Fortune card, and I think it looks awesome. So, there's the majors. I had some trouble finding artwork sources, but I got as many as I could.
soot sprite frame: https://www.redbubble.com/people/girlskater/works/21613437-soot-sprites-coming-out-from-corner?p=sticker
single soot sprite: http://cancersskinnylove.deviantart.com/art/Studio-Ghibli-s-Soot-Sprite-494142571
Majors
2. unknown
3. unknown
4. unknown
10. screenshot
12. Artist is called kyara36 but has made work private so I can't link it.
16. screenshot
17. artist name: hii10, work was deleted from pixiv
18. unknown