A SEO rank tracker module. It will very help full for specific ranking factor for each keyword.
Majestic (previously known as "Majestic SEO") is a backlink analysis company found at http://majestic.com that runs a business constantly analyzing the domains that make up the internet.
Mainly use this tool to check the Da and Pa values of the website
Provide 1000 free keyword suggestions
A cloud-based, web-crawling solution that helps enterprises to diagnose and fix technical and performance issues caused by poor SEO.
Keyword artifact: search volume of keywords in different countries, as well as ad clicks, keyword difficulty
Mangools is an SEO toolset that's great for bloggers, affiliate marketers, SMEs or SEO agencies.