We had created a "Learning Resource Library" (articles written by our SMEs) in a Canvas course shell that needed to be accessed by all courses. So I created a new subaccount for it and set the Visibility to Institution so anyone logged into our instance can view anything in that course. We also put a custom footer file (footer.html) that we iframe into every course page and assignment for copyright info. It's not the best solution for that but it works.
We've since switched to Confluence for our learning resources library using an add-on called External Share to create public links that we can put in our courses. But we still use that Canvas course for the footer and other "resources" that need to be accessible to any and all courses.