A few years ago, AngelList had a big database of companies in this stage. But today, this doesn’t seem to be available as they have pivoted what their product is. Where would you go to find a small company that has similar interests to yours?
Crunchbase has a 'Pre-Seed' filter on their company database. A quick glance shows these Pre Seed cos have still raised money though, so not sure if they're capturing the stage you're after. IndieHackers, maybe?
