If tooting a post or tracking a hashtag aren't quite what you're looking for, have no fear: the Mastodon API is very well documented. You can reference the documentation to build your own API request URL to suit your project needs.
With any social media usage, great power comes great responsibility. Be mindful when you're using the API for projects that you are respecting your instance's policies and community guidelines, especially around automated posting. This keeps it fun and wholesome for everyone.