Making a list remains hard. And up until a few years ago, doing your keyword research was much easier. You could simply check Google Analytics to see which terms people used to find your website. That is no longer possible. So you’re pretty much left in the dark about the terms people use in search engines to end up at your website. Luckily, there are some other tools which can make your keyword research a bit easier, and could help you speed up the process a bit:
Unlike similar tools, Serpstat is a page-oriented platform for in-depth competitive analysis. You can find competitors and define missing keywords for a single URL or even entire domains. You can also view historical position data for a range of pages organized by phrase, as well as see which pages have dropped in rank and their rank distribution as a percentage, which is very handy if you want to compare data from two different time periods or observe changes over time based on algorithm updates and other factors.
Long Tail Pro is a keyword research tool that helps you quickly find low competition keywords for your website. In particular, the tool is built for people doing SEO (search engine optimization) as opposed to people doing paid ads (Google Adwords PPC). I'm sure there are some advertisers that use the tool for paid ad keyword research, but the tool was built for SEO keyword research.