I will use the tool to pull in a lot of keywords related to a theme and group them into relevant topics. These topics will either become their own content page or will be combined with other topics to create a page. KeywordTool.io is similar to other tools out there such as Uber Suggest, which I've used for a long time, but it tends to produce more keywords and it provides search volume for the keywords.
The WordStream suite of Keyword Tools is an integrated and actionable set of keyword tools designed to help search marketers with keyword search, keyword suggestion, keyword grouping, PPC keyword research, keyword analysis, long-tail keyword research, and negative keyword discovery, going beyond the capabilities that a typical free keyword tool can offer.
To drive search engine traffic, whether through organic search or paid search advertisements, you need the right keywords, plus a process to expand your keyword lists over time. That’s where our free tool comes in. WordStream’s Free Keyword Tool gives you hundreds of relevant keyword results, plus additional, actionable information like competition level and estimated CPC, all for free!
Analyze Keyword Difficulty – Targeting difficult keywords with the highest competition is not always the best idea. The SEMrush Keyword Difficulty tool helps you determine keywords’ difficulties. By indicating a particular keyword’s percentage of difficulty, this tool helps you estimate how easy it would be to seize your competitors’ organic positions in the SERPs.
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).