I’d give Long Tail Pro a 4.5/5 stars for its’ ease of use, ability to generate a high number of long tail keyword searches of low to medium competition, check rankings and check Top 10 competition on any keyword search as to what the results of number of backlinks, domain authority/page authority and other pertinent ranking data from Moz.com’s api.
Usually, the various search engines provide their own keyword suggestion tools, which also include the number of searches for each of those keywords. The keyword researcher uses this information to select the correct keyword, depending on the SEO goals of the website. Around 20–25% of searches are very specific long tail keywords entered into Google every single day. It's easy to rank said keywords when there is the right amount of content and backlinks to match. Keyword research is a valuable and high return activity in the search marketing field.[citation needed]
3. Ninja Outreach: Full disclosure this is my own tool, and it is actually an outreach tool, so you may be wondering how it plays into Keyword Research. The fact is there are quite a few data points that NinjaOutreach gets for me that I find useful in keyword research, such as the articles that are ranking for the keyword in Google, their domain authority, their page authority, the number of backlinks they have, and other social and contact data. It's pretty valuable stuff, especially if there is going to be an outreach campaign tied into the keyword research. I wrote a great article with Jake from LTP showing the combination of the two tools.
Given you have a good idea of where to start and are fairly confident you are speaking the same language as your client, jump start research by generating related keyphrases and long tail variants with the ever so easy to use Google Autocomplete. This tool makes predictions based on what you are typing that are a reflection of Google search activity.
This database was built using data from BEFORE Google required active ad accounts to get good keyword data & before they started blending data together for similar terms. Even if you set up an AdWords account and spend significant sums of money with them, they may require you to run your ad campaign for 3 or 4 months straight before they will show reasonably precise data instead of exceptionally broad data ranges.
This makes Google Suggest a relevant source for keyword research, it contains a large amount of organic keywords very closely related to a full or partial keyword and can be used to find additional most searched appending keywords that make the whole keyword less competitive. Google Suggest can be researched through the Google Search website or through a compatible browser for a small amount of keywords but also in large scale using free scraper tools.

Offer Details: Offer expires 9/30/2018 (midnight Pacific Time), and is available only to qualified advertisers who meet the following eligibility criteria: Open to new and verified Bing Webmaster Tools account holders who own their own Website and open a new Bing Ads account; a “new” account is one that has been open fewer than 30 days prior to the date of coupon redemption. Your account will be evaluated daily to verify you meet the eligibility criteria. When criteria is met, a Bing Ads coupon will be sent to each qualified advertiser by email in approximately 3 business days from date of verification. See full offer details here.
2) SpyFu: I suggest to have paid account on SpyFu. I just need to find my competitors who using Adwords and review them using this tool. It will show me what ads and keywords they are using. Note that my competitor who paid for that particular keyword knows exactly that it is important for his business including recent trends. Also using SEO feature you can input any URL and find our which keywords they are ranking for.
Within a matter of seconds, Long Tail Pro showed me the top 25 Adwords suggestions for my seed keyword, with KC Scores already calculated! After scanning the list, I found a couple of keyword ideas that I wanted to drill further into. One of these was the keyword – legitimate work from home jobs. This keyword by itself would be very difficult to rank for (KC Score of 40) – but the new cloud version of Long Tail Pro allows me to easily grab up to 20 more suggestions based just on this keyword. I clicked the button to do that (as shown in the image below).
This is one of the best articles on Keyword research tool that I have encountered. However, To add more to this, I just wanna point out a tool (LSI Graph) for an outstanding long tail & semantic keyword research. After the recent Google algorithm, Google is now, however focussing more on context & semantics than keyword alone. What do you think about it?
What are people looking for on your site? These terms are keywords in the vocabulary of your actual audience and should definitely be added to your keyword list. Do not forget to look at the keywords people filled in that didn’t get any results: this was stuff people were expecting but didn’t find. You can look into the results of your internal search in Google Analytics at Behavior → Site Search → Search Terms.
I also hang out in SEO forums and groups and see KC scores tossed around and talked about and pretty much everybody is on the same page. Most agree that you can’t completely rely on the KC score (there are a few factors that can’t quantitatively be measured with a number) – but that the KC score is a VERY good indicator of the competition level for specific keywords. The following diagram realistically shows exactly what to expect from certain KC scores…
This isn’t the only tool that mines Google Autocomplete. There’s also KeywordTool.io, but this tool restricts results to ~700 keywords (more are available for “pro” members). Infinite Suggest is another alternative, but despite the name, I’ve found that it still doesn’t find anywhere near the number of keywords that Keyword Shitter finds. And there are tons of other Google Autocomplete miners too. Just Google “google auto suggest tool” for more. There’s also this tool from SEOChat which mines autocomplete suggestions from Google, Bing, Amazon, and YouTube.
For the first few months, there was certainly a transition period.  However, the new team was able to take over the reigns fairly quickly.  A big reason for the quick transition is because I had automated most of the business already.  So, the fact that I was stepping away didn't make a huge difference since all the sales, marketing emails, and many other details were already happening on an automated basis.