I suggest you Google Keyword Planner for Free ad if you want to get a better tool then I suggest you SEMrush. Google Keyword Planner is a good tool but has some problems. Using SEMRush, you can easily find the most profitable keywords. SEMRush is not only a keyword tool but it is also the best competitors analysis and overall SEO tool. Thanks, Mytechgoal.
Google or anything that uses the official Google API (like kwfinder) is what I would recommend. Accuracy is the most important thing, and no one will have better data than Google, especially for lower volume keywords.
One of the best Keywords Research Toolkit 2017 is Here. http://www.amitwebmarketing.com/best-keyword-research-tool-list-2017/
I can agree with the most of the bloggers here that the best keyword searching tools are Google Keyword Planner (free of charge), SEMRUSH and Jaaxy (not free, but more sophisticated).
Google Keyword Planner is the best place to begin keyword research. KWFinder is a long tail keyword research tool with a great interface. ... Keyword Explorer is a new tool by Moz that adds some extra dimensions to keyword research. ... Keyword Tool is a great starting point for keyword data mining.
Keyword planner is one of the easiest keyword searching tools.Spyfu is very helpful for keyword research, all search related elements you will get here.
Till now Google keyword planner is used but the best thing is to set new keywords yourself by checking competitor of the website.