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.
Product Hunt - A website that lets users share and discover new products
Alternative.me - Welcome to alternative.me, the source of better software alternatives. Finding suitable software was never easier.
Similar Site Search - SimilarSiteSearch helps you find similar, related, or alternative websites.
SaaSHub - Find and promote software that will help you grow your business or to be more productive.