SimilarSites - Easily find more sites like those you like.
Internet Indexer - InternetIndexer.com is a bundled collection of best seo tools.
Top Similar Sites - Top Similar Sites helps you find similar, alternative or related sites to any website instantly.
Ahrefs - Ahrefs is a toolset for SEO and marketing. We have tools for backlink research, organic traffic research, keyword research, content marketing & more. Give Ahrefs a try!
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.
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.