How to ease switching from one docs site to another for those using multiple projects?

[ssbarnea]

Combining documentation for multiple repositories and projects is not uncommon and at this moment I was not able to find a nice way to easy the navigator between sibling projects.

While it is obvious that those building documentation for multiple project will want to create their own theme (derived from material), so they reduce the maintenance churn, it is not clear how they can make it easy for users to switch projects while browsing documentation.

If anyone implemented something like this and can share it with others it would be awesome. I was considering using the top navigation bar but that would not scale well when number of projects grow. I think a dropdown kind of approach might prove more suitable for this.

I observed that @squidfunk is strongly against dropdowns, but at the same time I see that the versioning implementation is using dropdowns. I wonder if we could hack the version implementation to used it to switch between doc sites, especially for projects that do not use versioned docs. Basically instead of using a version, we would specify the project name and URL.