disclaimer: I am one of Datree.io founders. We provide a visibility and governance solution to R&D organizations on top of GitHub.
Here are some rules and enforcement around Security and Compliance which most of our companies use for multi-repo GitHub orgs. 1. Prevent users from adding outside collaborators to GitHub repos. 2. Enforce branch protection on all current repos and future created ones - prevent master branch deletion and force push. 3. Enforce pull request flow on default branch for all repos (including future created) - prevent direct commits to master without pull-request and checks. 4. Enforce Jira ticket integration - mention ticket number in pull request name / commit message. 5. Enforce proper Git user configuration. 6. Detect and prevent merging of secrets.