B.O.S. Stands for book of shadows . If you are an independent practicing pagan then your B.O.S. is limited only to your level of creativity . B.O.S.'s are where pagans keep the records they want to keep ( yes, sometimes there's other places as well like grimores ) But, a B.O.S. is as inclusive as you want it to be .
Some people use them to -
document research on sabbats and magic
journal about their spiritual life
write about deities
write the recipes, rituals, and spells they create
put spiritual art they create
and much more !
There is a commonality between art journaling and B.O.S. making and that is ..
It's yours , it's anything goes and only structured when and how you want it to be ( Though we discourage structuring an art journal beyond doing responses to prompts from time to time) , and both use your creativity a lot.
Art journaling can be a great complement to B.O.S. making I feel because , it can stretch your creative muscles in a similar way and " warm you up" for B.O.S. doings . Weather you've never had a B.O.S. and want to start one or you have one matters not . It can also help you separate what you find as spiritual and want in your B.O.S. from things you don't while giving you a place for those other things ( expressions) .
I have a club for creative art journaling ( A Free One ) and in it I give out prompts that can help inspire and stimulate . They are completely optional . Though, I'd really like to see the page of someone who's used one sometime ! (Insert goofy face here) Link to group - https://www.facebook.com/groups/Sabrinascreativeartjournaling/
ANOTHER BENEFIT is that with the help of tracing paper you can transfer things from your art journal to your B.O.S and thus the art journal can sometimes serve as an experimental rough drafting for B.O.S. pieces . For instance, if you want to draw a tree goddess and aren't confident about your drawing capabilities you can do it in your art journal , turn any mistakes into something playful and move on until you get it right . Then you can use tracing paper and transfer your final piece to your B.O.S. You can also of course, trace out parts of pieces done in your art journal to combine them with other creations .