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.
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!
Rank Tracker - Rank Tracker is an SEO tool for tracking and improving keyword rankings across multiple websites and search engines.
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
Nozzle - Nozzle is an enterprise level rank tracking tool. We pull over 400 data points from the SERPs so you can know everything that is happening for every search query that you care about.
Moz - Backed by industry-leading data and the largest community of SEOs on the planet, Moz builds tools that make inbound marketing easy.