I had a particular requirement for a project, so I wrote a plugin for it, and decided to make it available for ClassicPress.
ZP Multiple Roles allows administrators to allocate multiple roles to users.
The capabilities of a user with more than one role will be a combination of all the capabilities of the roles they have.
The plugin takes advantage of the fact that internally, ClassicPress and WordPress support multiple roles per user, they just don’t provide for it in the admin UI. ZP Multiple Roles provides the missing UI components.
It has many uses. One example is a site with two important plugins, both of which create custom roles for users to manage their operation. Now you can use one user account for both functions without having to install a much more complex plugin like User Role Editor.
Right now it’s an initial development release, but I’ve incorporated @CodePotent’s Update Manager right from the start so it will auto-update when I publish further releases.