Which tools or research strategies do you use to keep up with trends to build products!

Keto has been on the rise ... and people who were cognizant of the trend went ahead and made businesses around it ...

You name it ...Keto app's, youtube channels, blogs ... They are all thriving!

I was curious about the various tools Indie hackers use to keep an eye on such trends so as to jump in early and cash in on the trend by building products that cater to that particular growing niche.