This is an area I have been exploring myself for the past few months - especially as I work long shifts and want to be at home for my child.
I looked into freelance writing, blogging and affiliate marketing - dabbling in all. It's something you have to commit to to become successful.
There are other businesses though, such as selling online (ebay, etsy for example) - if you have a talent in making things selling via etsy will get you traffic and potential customers.
Whether you will find a unique business venture, I don't know - but you could perhaps find a unique product or niche. Do a bit of research.