1. Google Auto Suggest
Google's autosuggestions are a brilliant way to develop long-tail keywords variation. All you need do is start typing your keyword when you search on Google, and the search engine will give you available suggestions.
You will see some likely phrases, which tell you that people are searching for it. These suggestions might not align with your line of thought, but they will turn around your content and its visibility.
2. Google's Related Searches
The search engine result pages are a gold mine. Apart from the autosuggestions, it also presents you with related searches. They are below the organic results at the bottom of the search engine result pages.
Please take a look at those suggestions, it might give you more suggestions on what people are searching for on search engines, and they are much more personalized.
3. Your Google Search Console
Let's face it; your Google Search Console is direct info on what leads visitors to your website. It will tell you the exact long-tail keywords are leading visitors to your website. By exploring this list of keyword referrers, you will have an idea of the keywords generating traffic for you.
They are relevant to your business, but some may not be targeted directly by a page or post on your website. Look carefully at some of these keywords, and you can directly target them by creating an article on them.
To help you find them on Google Search Console, on your dashboard, go to a performance, scroll downwards and find queries. You can scan all the keywords presented for relevant long-tail keywords to create content around.
We use them and find them very helpful for identifying new post opportunities.
Thanks for the resource.