ScholPub can talk with you about your project even if you are not using a library platform. Initial support (overview but not training) may be available. Possible platforms include Omeka, PressBooks, PubPub, Scalar, and Wordpress using an individual account.
Omeka: open source web publishing platform for digital collections and exhibits
Pressbooks: open source platform for self-publishing books in multiple formats. Users can sign up for individual (self publisher) or Collaborate accounts for projects outside the scope of Open Scholarship Books
PubPub: free open source community-led publishing platform
Scalar: free open source authoring and publishing platform
WordPress: Web hosting, building, and publishing platform