Looking for a Network Graph alternative to systematically find & review non-PR branches in forks

As a maintainer, I’d like to be able to be able to find branches & commits in forks of my project which (for whatever reason) the authors have not started a PR for. See also this probot idea. The Network Graph is a partial solution, but it becomes unwieldy to use if a repo has many active forks, and also doesn’t seem to visualise open or closed PRs.

If anyone knows a tool (GUI or CLI or web-app, doesn’t matter) that does this, or even only touches on that usecase, I’d be happy to learn about it.

Looks like there’s a little something here: https://stackoverflow.com/questions/47022667/github-better-network-graph