Hello!
The New Readers team at the Wikimedia Foundation has been digging into how Wikimedia content is used offline globally and wanted to share with this list.
We've gathered what we know of what's out there (though surely there are more) and examined how the different solutions fit together and how they serve user needs for offline content. In the meantime, we're also developing use cases for the different products, types of content, and features. We plan to combine these analyses together to inform our future work and will share as we go.
https://upload.wikimedia.org/wikipedia/commons/3/30/Offline_Industry.pdf
We know there's loads more to learn - so please share if you have thoughts, critiques, or additions. I'll keep an eye on this thread or you can find us on meta: https://meta.wikimedia.org/wiki/New_Readers
Thanks, Anne