Being able to find search keywords that are related to a certain keyword is very important for me. For example, say that I want to know if there's a market for nose-scratching software. Then I can look for how often this keyword gets searched using AdWords keyword planner, and say that I find there are only 100 monthly searches. Okay.
But then, maybe most people who need nose-scratching software actually search for software to scratch my nose, which isn't picked up by my previous keyword. I want to know about this related keyword.
Now, I could use Google Trends for that, as it shows related keywords just like that; the problem is that Google Trends doesn't show related keywords for keywords with too low search volume, like nose-scratching software. These searches are still be lucrative for niche needs despite being low-volume, so I really want to find related keywords for them.
Does anyone have an idea how to get related keywords for low-volume keywords?