Another space that has a lot of potential is tooling that helps people skip the boilerplate that goes into setting up a new project. I'm working on one for React at https://divjoy.com, but I'm sure there are a bunch of other ways to make project setup easier.
After writing this yesterday I had an idea about stress testing, I had to test a few of my services in the past, but it has always been a combination of scripts and/or postman requests, it all feels very tedious, I saw there are already big SaaS players in the market, for example loader.io from sendgrid, but I feel like there is space for a simple tool, postman like, where I can just quickly configure some parameters and fire away from my machine...
If things go well and there is more demand for it, it can be integrated with a SaaS backing, WDYT?
and also this book is written just for your case, strongly recommend reading it: https://startupbook.net/