OK, so we have results here! After considering all the received feedback, we have finally decided it will be best to keep the early bird award criteria clean from any additional rules.
All plugins that had a compatible version available by the 3.1 release day 23:59 UTC, receive the "Early 3.1 bird" award. At the end there are 110 such plugins now. Some of them are still waiting for the initial approval checks even if they were submitted in time. Those will appear at the list once they are published in the Plugins directory.
To award those who answered the call for unit tests and Behat tests and have added them to their plugins, we are introducing a fresh new award called "Automated testing support". This award is given to recent plugins that support automated testing via PHPUnit and/or Behat. Recent means that the plugin has to be compatible with currently supported Moodle versions. Initially the award was granted to 177 such plugins.
I am very happy to see numbers of actively maintained plugins that are up-to-date with latest Moodle development. Big thanks and respect to all the maintainers!