(Updated November 2012)
Bing Ads Intelligence – A keyword research tool that allows you to build and expand on your keyword list in an excel interface and enables you to easily gauge the performance of relevant keywords on the Yahoo Search! and Bing networks.
Good Keywords – Windows software for Internet keyword research and management. Free trial available.
Keyword Eye – This is a neat visual suggestion tool to help you with your keyword research in many ways such as keyword brainstorming, gathering domain keyword and ranking data, helping affiliates to find a niche market and webpage keyword analysis (Defaults to Google UK for keyword data, can be set to US and other countries).
Keyword Extender – Combine keywords in different orders, add quotes, remove spaces, add suffixes.
Keyword Spy – Gather keyword stats, related keywords, cpc information, search volume, ppc and organic competitor lists.
Ranks.nl Keyword Combinations – The keyword combinations tool is made to help you combine, expand and manage your keyword lists, to use in PPC (Pay-Per-Click) campaigns.
SEMRush Competitor Research Tool – The free version shows organic and PPC competitor list as well as keyword ranking positions. Paid version offers far more information and statistics.
SEOBook Keyword Density Analysis Tool – Free tool to help you find the most common words and phrases on a page.
SEOBook Keyword List Generator – Web based software which allows you to generate a large number of keyword phrases based on permutations of keywords you enter.
SEOBook Spider Test Tool – Tool reads the source code of a page and tries to show it as search spider may see it.
SEOBook Webpage Comparison Tool – Tool compares the page titles, meta information, and common keyword phrases between different phrases.
Serp Analytics Top Keywords – Great to get ideas. Click on any of the keywords for details on searches, cpc, ranking sites etc.
Traffic Travis PPC & SEO Keyword Tool – Free SEO Software. Use Traffic Travis for both on and off page analysis.
Word Hippo – Vocabulary & keyword resource.