It sounds like Mattel will disallow the use of AI generated images in future official works:

The Dungeons & Dragons role-playing game franchise says it won’t allow artists to use artificial intelligence technology to draw its cast of sorcerers, druids and other characters and scenery.

https://www.theglobeandmail.com/world/article-dungeons-dragons-tells-illustrators-to-stop-using-ai-to-generate/