There are several ways how you can 
contribute to cheat.sh and make it better and more useful:

1. Suggest a GitHub repository (or other information source) to be attached to cheat.sh. Just create an issue for it, where the name and the URL of the repository is specified. Please keep in mind, that the repository's license has to permit its usage by cheat.sh;
2. Create an adapter for some repository and add it to cheat.sh;
3. Create a Editor plugin for cheat.sh;
4. Create a new cheat sheet in one of its upsream repositories;
5. Go through the list of open issues, and try to fix some of them, or at least understand and share your opinion about them, if you have it.