The team at E2M is taking this opportunity to analyze other significant (and free to use/try) keyword research tools out there. We are asking ourselves what data and logic should ideally go into keyword research, how this logic can be programmatically applied to the creation of tools, and what the best ways are to consolidate and use their output. Here’s a quick look at 25 other keyword research tools, some well-known and some you’d do well to know. These are not alternatives to the AdWords Keyword Tool on their own, but each of them performs some function of the AdWords tool in its own unique way, and all of them aid and abet your keyword research quite well.
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 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.
Can't go wrong with the Google Keyword tool, SEMRush and Google Trends. The Keyword tool for volume estimates, SEMRush to see what keywords competitors are ranking for/targeting, and Google Trends to make sure the traffic is actually coming from countries I'm trying to target. Gives a relatively accurate picture of when to expect traffic spikes and seasonality insight.
The link back to googles API is crap – it keeps coming up with password authentication which renders it virtually useless when trying to find your own rank. Sells you the software initially. But then tries to sell you a load of stuff afterwards which effectively tells you the first version you have already paid for is useless without the extra “bonuses”. Not a nice way of doing business
For a long time, I wanted to develop a tool for content marketers that would assist in the process of coming up with blog ideas and subjects. Upon researching developers for this concept I had, I stumbled across  Long Tail Pro, and realized instead of developing a tool myself for fellow bloggers and content marketers, I would throw my support behind this one.
It’s very easy to use, fast and smooth and gives you tons of Long Tail Keywords. You only pay for the web based software once, so there are never any monthly fees. I’ve also been impressed over the years at how easy it is to update. These updates are free and the creator (Clever Gizmos) is always moving with the ever changing world of SEO and updated API’s to keep his program up to speed and fresh.
In a nutshell, Long Tail Pro helps you quickly find keywords in bulk based on a seed keyword that you input.  In addition to returning hundreds of related keywords, the tool also shows search volume (monthly search volume), advertiser bid, number of words, rank value, and my favorite Keyword Competitiveness (helps you judge the competition and keyword difficulty).