I’m happy to help if I can. I’ve been the series editor for a set of open textbooks in philosophy, working with folks in this community. Many of the thoughts I have are likely already in the Rebus Guide to Publishing Open Textbooks that you have referenced. But if you have any specific questions I can try to help as best I can!
In terms of collaborating with other educators/authors, I have found some success in posting to the Rebus Contributor Marketplace forum; those posts will sometimes go out in the Rebus newsletters, which reach a good number of people. I have sometimes also used social media to seek contributors, or email lists in my discipline.
For questions about accessibility, I’ve used this very “Help and Questions” forum here for specific questions, and we also had an accessibility checklist that we used for each book in the series, and that we also published at the end of each book (e.g., here is the one for the Ethics book). I haven’t reviewed those accessibility checklists in a few years, though, and I might consider revising them at some point! I have appreciated the BCcampus Accessibility Toolkit, which provides helpful guidance.
