I suggest you do some research into keywords first and also consider what you are able to write about! SY
Never go in search of high paying niches and keywords but write in a niche in which you are the master, which in turn will help you to keep the tempo up in the long run.
Anything you like to write about. Remember, you have to generate a lot of pages about a topic to make money from it. (Unless you know a lot about micro marketing) I do micro marketing, but I also do marketing for one big blog that I have because I enjoy its topic. So pick a big topic that you enjoy a lot Then pick a super defined niche that you can rank on Google for after building a few pages.
I will suggest the high paid niche is your mind. What you can right effectively then you can earn a lot
There are a lot of niches that pay well and you will find a lot of high-paying keywords list. You can use such lists to decide what can be the best niche for you. However, I think web hosting is a nice option.