Here is a list of Free search engine optimization tools that I use for Search Engine Optimization to obtain high ranking on search engines:
FREE: Ontology tool – finds related keywords using the Google ~ search. (http://www.gorank.com/seotools/ontology/)
Various Prices (Can be FREE or Paid Membership): WordTracker – web based leased product which has many more features than the other tools. WordTracker traffic is generally more representative of actual traffic than Overture’s tool since many fewer automated bots scour its data collection network than Overture’s. (http://www.wordtracker.com). This tool can be used free for one day, but you will have to register. WordTracker will send you a temporal link, that you can use to log into your temporal account and research keywords for your website.
Various prices: Keyword Discovery ‐‐ deep database of keyword data. Contains historical data. Some of their partners made them sign a non disclosure agreement. The database may not be as clean as the WordTracker database, but it does contain more data. (http://www.keyworddiscovery.com/)
FREE: Overture Search Term Suggestion Tool – offers search frequency for the prior month throughout the Overture network. Please note that many bid checkers and other automated bots cause this number to skew high. (http://inventory.overture.com/d/searchinventory/suggestion/)
FREE: Google Keyword Sandbox – shows related search terms but not search quantity. (https://adwords.google.com/select/main?cmd=KeywordSandbox)
FREE: Google Search Suggestion Tool – auto‐completes search queries to help you find more related search terms (http://www.google.com/webhp?complete=1&hl=en)