Your Tools
There are tons of tools available for KW research and analytics, many of them free, some a one-time purchase and others a monthly subscription. For those still learning, a free tool is probably the wisest choice, at first, in order to learn what can be accomplished with tools. Then, you’ll be better able to select the tool that best suits your needs.
Much depends on the nature of your work, too. For instance, some sites will require a very granular analysis of referrers while others might be more interested in less detailed data. Many tools do a great job in one area, and fall short of the mark in another.
That’s why many SEOs will have a number of different tools that they draw upon, depending upon what their immediate goals are. I know several that use a handful of tools on each site audit, in order to extract the information they want. Others may stick with nothing more than Google Search Console and an Excel spreadsheet to drill down to the necessary level.
Unfortunately, the majority of the tools out there have a lot in common. In fact, some are nothing more than copies of others, offering nothing new. Most of us will go through a long array of tools before we finally settle on a collection that we feel comfortable relying upon.