LibHunt - LibHunt tracks mentions of software libraries on relevant social networks. Based on that data, you can find the most popular projects and their alternatives.
Rage Grade by FullStory - Benchmark your customer frustration
GitSpo - Measure & engage your open-source community
Shuffle for Bootstrap - Bootstrap drag and drop builder for busy developers.
AlternativeTo - AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
Tailwind CSS - A utility-first CSS framework for rapidly building custom user interfaces.