One of my best friends is married to a distant cousin. All they do is sell on ebay/amazon for a living for probably close to 12-13 years now. They are only a 2 person team, which limits what they can do, but I guess it's good enough for them. They have branded their own beauty products such as fake eye lashes. I know my cousin will collaborate with several famous instagram models. Basically a lot of buying wholesale from China and reselling, rebranding products at a much higher cost.
Also of course some people can make a living off youtube if you can generate enough views. There are many that have made a decent amount based on their content. Obviously not everyone is going to be making nearly as much as Ryans World. I think he's cracked like 40 billion total views and has probably made more then $100 million off of youtube alone. Pink Fong that made the popular baby shark video has probably made over $50 million from youtube alone. Blippi probably made several million off his channel as well. There are some very amateurish toddler/preschool learning videos that capitalized early on that have probably made them over $1 million. There's a dad and his 2 teenager/maybe young adult aged kids that has a youtube channel solely based on racing hotwheels. Their content is very amateurish, but they are closing in on 300 million total views and probably knocking on a $1 million total revenue. Some guy that restores sneakers started making exaggerated videos on youtube. He started to get so popular he stopped doing sneaker restorations so he could focus on his youtube videos instead. I think his channel has over 150 million views total which is pretty damn good. These are just small time examples. Look at all the gamers out there that has banked. My cousins best friends brother is a OG youtube gamer that made millions off youtube. I think he went a little crazy though, but he was one of the first gamer to make millions from youtube. If you have content good enough to break $100 million views a year you can definitely make a good living off of that assuming you average about $2-3 per 1000 views.