I have been using the beta version of PlanetScale for a while, and it is extremely cool. It's using the mature technology that powers Youtube to provide a developer experience for databases similar to what Vercel and Netlify provide for hosting: It will give you a database branch for each Git branch and help you manage the workflows around it.

And it is the first truly serverless relational database offering that I am aware of. The cost scale to 0, so it is perfect for small projects, but that same instance will scale to support massive load when you need it.