1) Google Keyword Planner: This tools is fantastic because it can help me to identify long tail keywords for my niche. It is official Google’s tool and it has the recent trends and keyword variations. For example you may think that this keyword is great “buy ipad air in liverpool” but Google may suggest “iPad air sale Liverpool”. Yes, not often it is accurate but when I’m using it alongside the other tools – I can get clear idea.
Most people who use the Google’s auto complete feature to generate keywords that they include in their blog title or page find Soovle to be a very useful tool. This tool moves the auto complete feature a step forward by getting inputs from several sources like Amazon, Yahoo, Wikipedia, Bing apart from Google itself. This assists the user to generate keywords that drive online traffic in a better way. The default is usually set to Google but you can switch to the other options at your own will and view how the outcome keeps on changing. You can experiment with a broad range of keywords by running them through a specialized tool such as the keyword inspector as a way of extracting value that will boost your sales on Amazon.
Google Suggest isn’t exactly a tool, but I’ve found that it can be useful for identifying potential keywords. As you type a query on Google.com, Google Suggest recommends search queries based on other users’ search activities. These searches are algorithmically determined based on a number of purely objective factors (including popularity of search terms) without human intervention. The Suggest dataset is updated frequently to offer search queries that seem to be trending upwards. This feature is largely one of the reasons that you may see repeat traffic of seemingly long tail keywords. By identifying these long tail keywords and optimizing for them, marketers can capitalize on seemingly obscure keywords with little competition.

The limit on manual keywords could be higher.  I personally wish we could input 10,000 keywords at a time, instead of 200.  However, I understand the costs that Long Tail Pro has to maintain each time a new manual keyword is input.  Not a deal breaker, I just wish the limit was higher. (To be fair, I don't think most keyword tools have a bulk manual option at all).