Ask HN: SaaS idea that is simple enough for a one-man-shop?

I wonder if anyone else is having the same dilemma.

I'm wanting to start a SaaS business to run as an independent developer.

My problem is a lot of the ideas that come to my mind I can see would eventually require a team of 3-10+ people to operate and at this stage I'm not looking for that.

The sweet spot for me is where I can make a living from the product while still being able to keep things essentially as a one-man-business.

Do you have any suggestions for a profitable-for-one-person SaaS product?