The Autorest project is referenced by other projects like the autorest csharp projecct which does mention that it is a "Extension for AutoRest (https://github.com/Azure/autorest) that generates C# code"
It took me some time to figure this out How do I find out what the other extensions are?
Both autorest and autorest.csharp are repositories in the Azure organization.
If you're just looking for the other repositories within that organization that are also autorest extensions, you can perform a simple GitHub query for repositories that follow the same naming convention.
EDIT: For this particular project, this document listing the code generation extensions is maintained.