Content Idea Generator - Free tool creates ideas for your content marketing strategy
Seolyzer - Seolyzer is the ultimate SEO tool that provides you with all the information you need to improve your website’s health and performance.
Content Marketing Stack - A curated directory of content marketing resources
SEOmator - SEO website analysis & audit tool
Zestack - Stackoverflow for marketing & growth
Whatsmyserp - Powerful Rank & Serp Tracking. Completely Free.