As there are two kinds of SEO: 1. On page 2. Off page . Here are some suggested tool:
some good on page seo plugins if you're running a Wordpress website. If you're running Joomla site then here are
some good plugins for you. However, you can search Google always if you're running a different module.
For Off page SEO, I will recommend using Market samurai for finding niches, scrapebox for url harvesting, SEO powersuite for dominating your competent and Ultimately No hands SEO for unlimited link-building. Thank you :)