Gitrep is described as 'allows you to search repositories by community created tags and their descriptions, along with apply personal tags that you can use for your own personal organization' and is an website in the Development category. There are three alternatives to Gitrep, not only websites but also apps for a variety of platforms, including Mac, Windows, Chrome Web Store and Cloudron. The best alternative is Astral, which is both free and Open Source. Other great sites and apps similar to Gitrep are Oh My Star (Paid) and GitHub Stars Tagger (Free).
Astral pulls down all of your starred repositories on GitHub and allows you to organize them using one or more tags. = Tags = Tags are the bread and butter of Astral. Simply add one or more tags to a repository, and keep them organized however you like.