You could go browse Patreon. Questionable Content is essentially a one man show, though it started as him and his girlfriend/first wife (she apparently did tech support and marketing, he produced the content). He has apparently been making six figures for some years, even before Patreon was a thing. Girls with Slingshots is another webcomic supporting its author.

I believe they both do a certain amount of T-shirt sales and the like, but the comics themselves are the main draw. T-shirts are just a means to monetize the comics, along with Patreon, ads, etc.

There are many other Patreon supported sites out there. You could go looking for some examples of stuff similar to the kind of content you have in mind (I assume you have no plans to be a web comic artist).

I make some money from my low traffic websites where I publish all original content produced by me. I occasionally get a little ad money, but most of the income is from Patreon and tips. I have never figured out how to make money from affiliates. So people are basically straight up paying me voluntarily to produce content online. I hope to grow the traffic and improve the monetization.