Kparser is progessional keyword research tool that gives thousands long tail suggestions from Google, Bing, YouTube, eBay, Amazon.
Sitechecker is free on page SEO checker designed to make audit of over 100 technical parameters and say how to fix every founded mistake.
Quality SEO Content Software: Improve Your Content Optimization. Make your content perfect for both people and search engines.
LinkStrategy specializes in offering detailed analysis of competitor's backlink profile to help to find effective link building strategies, valuable backlinks, and anchors in a few clicks.