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!
HypeStat - HypeStat is free statistics and analytics service, where you can find information about every website.
OnCrawl - OnCrawl is a SEO crawler and log analyzer that helps you improve your SEO performance. Increase traffic, rankings & revenues. Start your 14-day free trial.
Site Rank Data - View historical rank information of websites via time series charts.
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
Q-Stats - Get free marketing insights for every question on Quora.