SERPStream is a 100% free SEO tool. Members can keep track of their site's Search Engine Results Page position with updates as frequent as a dozen times a day. SERPStream have a great newsletter, sends email alerts, and have a state of the art keyword rank tracking dashboard.
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
Page Optimizer Pro - Page Optimizer Pro is an on-page SEO tool, allows marketers to produce flawlessly optimized pages for Google with ease.
SEO PowerSuite - Get all SEO tools in one pack - download free edition of SEO PowerSuite and get top 10 rankings for your site on Google and other search engines!
Schema App - Schema App empowers the Digital Marketer to own their schema markup strategy through to implementation without ever writing code.
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
BacklinkSEO - BacklinkSEO is an SEO tool, which is designed to build and monitor backlinks with ease.