What are some of the best SEO Tools?

I always get this question during my Meetups, so I decided to run a list that answers this exact question. This handpicked list of SEO and Marketing tools is maintained by Saijo George . The idea behind this site is that you can find all the tools you would ever need as an SEO or Marketing Consultant, in one spot. If you folks think I have missed something that is really awesome, please do let me know via Twitter or LinkedIN and I will add them in here.If you like this, you might also like my SEO newsletter - tl;dr Marketing with links to stories that impact SEO, SEM and Social Media.