Curatedseotools.com - Curated directory of the best SEO tools.
SEO Marketing Hub - Learn SEO for free
KatLinks.io - Rank Higher and Get More Traffic with an affordable SEO Tool
SEO Minion - Chrome extension & Firefox add-on to help you with SEO
SERPstash - Free SEO tools for Entrepreneurs
SEO Asked - An archive of Googlers tweets & answers on SEO.