I love APIs. This is why I'm using HashNode for my blog/portfolio project. HashNode doesn't give you a RESTfull API, and there are many limitations with its GraphQL, but it is enough for my personal project.
On my project https://codetopg.github.io/. ATM, I'm using two public web APIs. Open Weather and HashNode. I'm planning some workarounds to turn HashNode into my backend for a portfolio project.
There is an APIs Hub that maintains by the GitHub Community at https://publicapis.dev/
Where you can find the API that you need for your project, or you can join the community on GitHub https://github.com/public-apis-dev/public-apis.