Voting starts in March for the Drupal Association Board election.
Here's a thread to propose that flags should be extended to work with any entity in Drupal, not only nodes + comments + users.
There's another thread () that has touched upon this, but the main discussion there is about making flags fieldable.
(I'd be surprised if this feature request hasn't already been discussed among the Flag maintainers, but I really couldn't find an issue for it. And if there's a good reason *not* to have flags on generic entities I'd be happy to hear it.)