Similar Site Search - SimilarSiteSearch helps you find similar, related, or alternative websites.
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.
SimilarSites - Easily find more sites like those you like.
Top Similar Sites - Top Similar Sites helps you find similar, alternative or related sites to any website instantly.
Google Similar Pages - Google Similar Pages is an extension by the Google for its Google Chrome web browser users.
Product Hunt - A website that lets users share and discover new products