I wrote a quick script through Github's API, and found 10 users[1] matching the criteria:

* starred any screeps repo before May 2017, and no other screeps repo since then

* no public contributions or events since April 2017

If someone has some time to do further filtering, ensure the users have not starred any GitHub repo since May 2017

I didn't go through forks but that would also be an avenue.

[1] https://gist.github.com/aramperes/2363dc3434de6b494b28b5a658...