You will have to narrow your niche but look at the health, wealth and relationship markets. Honestly there are niches everywhere..
All the niches are overloaded and I mean OVERLOADED like hell. So just pick a niche you like, you think you can create quality content for it and just start. Trust me the more time you choose, the more time you will waste, it is useless, everything is full. So if you're good at something focus on it and begin a project, you will develope with the time.
As mentioned above, all markets are pretty saturated, but if you dig you can find some subniches of niches with their own very specific needs. People want more and more of a personal approach today and solution to their specific problems. Just as an example, you can go to Amazon and search for, let's say some piece of gym equipment. While there are might be a ton of positive comments, some people still would want some specific features, additional options, etc. By providing a product with this features, you can win this part of the market. The same logic applies to non physical produts as well. Another thing is to target people with in one niche, that might be interested in your product as well. Like for example, targeting poker players with forex trading ads. Just be creative with your approach and always test.
I hear crypto currency is all the rage at the moment! Even with saturated markets, the right angle can net you huge profits in any niche. Facebook advertising and Shopify stores have proved this works.
Like the other says, just about anything you can think of that already exists is going to be saturated. The best thing you can do is some research, and find one that is ever-green. Just like any other site, you just have dig in.... 1: setup a site better then others. 2: provide better quality content then others. (500-1000) is no longer the norm, you need to be thinking about 2000-3000-4000 or even 5000 words if you want googles attention. 3: acquire high quality backlinks. as long as you follow google guidelines.... then you may see something happen within 1-2 years.... (that is about the norm before you start seeing results....) and the only except to this is if you have a winning product, and using FB/google ads for instant results...
The motivation these days should be about yourself. How motivated are you to tackle the topic and stand out from the crowd.