This type of question comes up a lot. I can appreciate you are using the highly regarded problem / solution, vitamin not a painkiller approach to finding an idea, but STOP!

HN probably isn't a good place to start. We're not typical. For example: I want a tool to help me memorize new VIM commands...probably not a good business.

Start with a problem you care about...cause you'll be working very hard on it, for a long time, to turn it into a business. When you find a problem, seek some sort of confirmation. Then, build an mvp and see if folks will use it.

Good Luck