During Hacktoberfest, you're probably looking to contribute to an awesome open source project. Gatsby is a great project to contribute to because you can learn about Gatsby while tackling a list of carefully curated issues, prepared especially for Hacktoberfest.
Back up. What's Hacktoberfest?
Hacktoberfest is "a month-long celebration of open source software run by DigitalOcean in partnership with GitHub and Twilio".
We love our docs! Improving docs is a never-ending effort, and we have tons of stub articles (docs we want to exist, but haven't been written yet). If you're interested in contributing to the docs and doing some writing, check out docs issues labelled with Hacktoberfest.