Ever since Google announced the impending demise of the AdWords Keyword Tool and their preference for its new avatar – the Keyword Planner, yet another hot discussion has sprung up in the SEO community. This time, strong adherents of the free-for-all ideology are riled at Google’s decision to make the Keyword Planner accessible only to marketers who’ve explicitly signed up to Google’s AdWords (which is one step more than having a Gmail account), taking it closer to being a paid tool in future! I don’t see this as a hindrance, because most other keyword (or other) tools require you to create an account and sign in before you can use them, even if they’re free. But if Google does it, we have reason to pounce on them, don’t we?
Unlike similar tools, Serpstat is a page-oriented platform for in-depth competitive analysis. You can find competitors and define missing keywords for a single URL or even entire domains. You can also view historical position data for a range of pages organized by phrase, as well as see which pages have dropped in rank and their rank distribution as a percentage, which is very handy if you want to compare data from two different time periods or observe changes over time based on algorithm updates and other factors.
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.
This tool allows you to type in your keyword phrase or keyword in the field that is provided and it will generate a long list of suggested keywords.  It has three button level and you can perform a deeper search by clicking on button level 2. You will get a list of keywords or keyword phrases that are related to the original list provided in level one. If you want to continue further, you can click on level three and then click the link at the bottom to download the data. The tool can assist you to discover those keywords that your competitors could be ignoring and use those opportunities to create fresh targeted content.

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).