Keyword Research and SEO are entire industries today. There are tools like ahrefs and semrush that promise to give you "trending" topic keywords for a sum of monthly subscription money.

However, you can discard all their claims using a similar logic that you use to discard the claims of Astrologers, Voodooists, Stock Experts who "recommend" stocks, etc:

1. If an Astrologer knows the future of everyone, wouldn't they profit massively from it themselves using the information rather than telling the trick to everyone else (just for a pittance)?
2. If a Stock Expert knew that a stock's price will go up (and how much), won't they invest thousands and make millions themselves instead of giving those "tips" to "subscribers" and again, earn only a pittance?
3. If SEO and Search Marketing companies knew exactly which keywords can rank your blog or site in the Google Search Engine, won't they write articles on those topics/keywords themselves and profit massively with the page views instead of revealing that secret to you for merely a few cents!

We're obviously being denied the benefits of so called advances in algorithmic search, as evidenced by the poor showing of Google Itself in unusual searches. For example, if you search images for "runners wearing green hats -shamrock -st. -patrick" Guess how many runners wearing green hats you get?

So search is hard? I think it's more likely that Google and everyone else is more interested in selling you a hat than helping you find a picture of a runner in a green hat.