The Painted Art Journal may focus primarily on paints, but I think it has broader appeal across a spectrum of mediums. It introduces a range of other materials, such as pastels, stamps and printmaking, collage, natural dyes, etc and the author explicitly encourages experimenting and using whatever materials you have or that work for you, regardless of what she uses in the demonstrations.
I also think this is a project sourcebook that could potentially appeal to many kinds of artists, whether they're interested in art journaling or not. There are tons of exercises, prompts, and thought experiments to play around with, many of which either don't involve a journal or could easily be expanded to include whatever form you want to work in. The real strength of this book is the way it offers a wealth of tools for you to choose between as desired. It encourages exploration, self-discovery, and the expansion of one's artistic practice, even if the only audience you're working for is yourself.