https://metroretro.io - started as a hackathon project in 2016. I found people using the barely functioning prototype a year later for actual work meetings and decided to started improving it. I went perm on the project 3 years ago and this year passed 10k MRR (100% self funded). Still doing all the dev and ops solo, but I have two co-founders doing all the sales, support and finance stuff. We are going for a specialized whiteboard for software/agile angle rather than generalist whiteboard app currently.

I think I'll be working on this product for a long time as I believe there is a new generation of collaboration software coming to replace the current leaders and I would like to be one of them. I think about this product night and day, and wouldn't want to be building anything else!