The best online business for you would be the business you are able to most efficiently and effectively run without ever having thoughts of giving up.
You have to ask yourself what are you passionate about? How can that passion help someone or bring joy to someone's life? Think about your passion in product form. Think about your passion in service form. For example, hair stylist love to transform their clients into something more beautiful. The need here is for women to feel good and the hair stylist fulfills that need by completing the service of doing their hair.
More times than not, people are passionate about the businesses they decide to get behind. It's important for you to first be sure you're not just doing it for the money but creating your business with intention and with the ability to fulfill a purpose.
If you need any help with branding your business or setting up a business plan, request a call I'd be happy to assist.
I hope this helps!