Crunchbase - Crunchbase is a platform for discovering industry trends, investments, and news about companies around the world.
Ahrefs Backlink Checker - With the world's biggest index of live backlinks (over 15 trillion), Ahrefs Backlink Checker will show you the most complete backlink profile for any website.
Owler - Owler is a crowdsourced data model allowing users to follow, track, and research companies.
Whatsmyserp - Powerful Rank & Serp Tracking. Completely Free.
CB Insights - CB Insights is a company database for the venture capital and corporate development community.
Backlink Tool - A backlink tool to index your links quickly and freely.