If you are building a project, you might need data to be used by your app. However, constructing your own database may not be feasible because of the time and resources needed to build and maintain one. In that case, where do you get the data from? That is where APIs come in handy. People have already built their collected their own data and are willing to let people access it for their own uses with an API. All you have to do is send an HTTP request to the server and you will get the information you need.
With APIs scattered all over the internet, someone has taken the initiative to create a GitHub repository to create a list of publicly available APIs. With all the links stored in one place, you can conveniently see what APIs are offered.
APIs in this repository are categorized depending on what data is offered. Click on the category you want and browse what is available. Each entry on the list has a name, a description, and whether or not it requires authentication, supports HTTPS, and supports CORS. Pay attention to those last three columns as it will help you determine if the data is usable for your application. It could also affect how you build your app around that API.
So the next time you need quick data, check out the repository. If you want, if you have your own API or know one that is not on the list yet, contribute to it and expand the collection!