Sometimes the game isn't immediately visible on the github.io page, but the code is in the repository. If you find a GitHub repo for a game (e.g., github.com/username/retro-games), look for the link in the "About" section on the right side of the page, or simply add github.io to the URL structure if you know how Pages works.
This is an old but gold method for unblocked github.io pages. unblocked github io
How it works: Google Translate fetches the page through its own servers, acting as a proxy. The firewall sees translate.google.com, not github.io, so you get through. Sometimes the game isn't immediately visible on the github
Subreddits like r/UnblockedGames and r/SchoolLaptops frequently post new GitHub.io links. Because Reddit is often unblocked, you can find "fresh" links that haven't been added to the school's filter yet. How it works: Google Translate fetches the page